Home
Supplier Discovery
Tools & Hardware
Drill Bit
Insert Tricone Bit Factories & Companies
Filter
Category
Chemicals
Construction & Decoration
Electrical & Electronics
Manufacturing & Processing Machinery
Metallurgy, Mineral & Energy
More
Management Certification
Others
ISO9001:2015
ISO 9001
ISO45001:2018
OHSAS/ OHSMS 18001
More
R&D Capacity
OEM
ODM
Own Brand
Others
Annual Revenue
<1 Million USD
1 ~ 2.5 Million USD
2.5 ~ 5 Million USD
5 ~ 10 Million USD
10 ~ 50 Million USD
More
No.of Employees
Less than 5 People
5-50 People
51-200 People
201-500 People
501-1000 People
Province & Region
Anhui
Beijing
Fujian
Guangdong
Hebei
More
about insert tricone bit
Technological Innovation
Reliable Supply Chains
Substantial Manufacturing Capabilities
insert tricone bit
100+ factories verified
Hejian Hengji Bit Manufacture Co., Ltd.
Send Inquiry
7 7/8'' 200mm IADC 437 TCI Tricone Bit Insert Chisel
US$
350.00
-
980.00
1 Piece
(MOQ)
17 1/2'' IADC 537 Tricone Insert Tooth Drill Bit Civil Engineering Application
US$
3,000.00
-
5,000.00
1 Piece
(MOQ)
4 3/4'' 120mm Tricone Button Insert Drill Roller Cone Bit Drill Tool
Negotiable
1 Piece
(MOQ)
API Standerd 9 7/8 Hole Opener TCI Insert Teeth Tricone Bit
US$
100.00
-
3,000.00
1 Piece
(MOQ)
1/4
Hejian Dingtong Drill Bit Manufacturing Co., Ltd
14 yrs
·
Manufacturer/Factory & Trading Company
Send Inquiry
Long-Life Insert Tooth Tricone Drill Bit for Hard Rock Drilling
US$
500.00
-
3,000.00
1 Piece
(MOQ)
High Durability Insert Tooth Tricone Drill Bit for Rotary Drilling Project
US$
500.00
-
3,000.00
1 Piece
(MOQ)
6 1/2" IADC 517 Insert Tricone Drill Bit
US$
366.20
-
5,042.96
1 Piece
(MOQ)
9 7/8" (250.8 mm) IADC 637g Insert Tricone Bit
US$
366.20
-
5,042.96
1 Piece
(MOQ)
1/4
Sinotai Petroleum Equipment Co., Ltd
18 yrs
·
Trading Company
Send Inquiry
Tricone Drill Bit TCI Tungsten Carbide Insert Roller Cone Bit for Oil Well Hard Rock Drilling
US$
500.00
1 Piece
(MOQ)
Hole Opener TCI Tungsten Carbide Insert Rock Tricone Roller Cone Cutter Bit for Well Drilling
US$
500.00
1 Piece
(MOQ)
Tricone Drill Bit TCI Tungsten Carbide Insert Roller Cone Bit for Hard Rock Drilling
US$
500.00
-
5,000.00
1 Piece
(MOQ)
165mm IADC537 Rolling Bearing Tricone Bit Tungsten Carbide Insert Bit for Well Drilling
US$
700.00
-
750.00
1 Piece
(MOQ)
1/4
Glorytek Industry (Beijing) Co., Ltd.
5.0
Send Inquiry
High Quality Tungsten Carbide Inserts Tricone Bit Manufacturer
US$
1,000.00
-
1,500.00
1 Piece
(MOQ)
6 1-2inch TCI 517 Carbide Insert Tooth Three Roller Bit/Oil Well Tricone Bit for Sale
US$
980.00
1 Piece
(MOQ)
Hot Sale High Quality Tricone Bit Drill Bit Drilling Tool Insert Tooth Bit
US$
1,000.00
1 Piece
(MOQ)
Tricone Bit Drill Bit Drilling Tool Insert Tooth Bit Drilling Tools All IADC
US$
1,000.00
1 Piece
(MOQ)
1/4
Beijing Dazheng Yongye Technology Co., Ltd.
15 yrs
·
5.0
·
Manufacturer/Factory & Trading Company
Send Inquiry
Tungsten Carbide Insert Tricone Bit 8 1/2 Inch Well Sealed Bearing
US$
280.00
-
300.00
10 pieces
(MOQ)
2025 API Tungsten Carbide Insert Bit Tricone Bit for Oil, Water and Gas Drillin
US$
78.00
-
80.00
10 pieces
(MOQ)
Tungsten Carbide Insert Tricone Bit
US$
280.00
-
300.00
10 pieces
(MOQ)
Tungsten Carbide Insert Tricone Bit 8 1/2 Inch for Oil Well IADC 517
US$
80.00
-
85.00
10 pieces
(MOQ)
1/4
Suzhou Energy Tool Co., Ltd.
Send Inquiry
Factory Tungsten Carbide Insert Tricone Drill Bits for Mining Rock
US$
900.00
-
5,000.00
1 Piece
(MOQ)
Heavy-Duty Tungsten Carbide Insert Tricone Rotary Drilling Bit
US$
1,000.00
-
4,000.00
1 Piece
(MOQ)
7-7/8 Inch TCI Carbide Insert Tricone Coal Mining Rock Drill Bit
US$
1,000.00
-
2,000.00
1 Piece
(MOQ)
Tungsten Carbide Insert Tricone Drill Bit for Oil and Water Well
US$
900.00
-
1,500.00
1 Piece
(MOQ)
1/4
Beijing Jincheng Mining Technology Co., Ltd.
Send Inquiry
8-1/2" Tricone Bits/Button Insert Bits /Roller Cone Bits
US$
100.00
-
1,500.00
1 Piece
(MOQ)
Factory Price TCI Tungsten Carbide Insert Tricone Cone Rock Bits for Water Well Drilling
US$
1.00
1 Piece
(MOQ)
Insert Tooth Water Well Drilling Tools TCI Tricone Rock Roller Bits 10''
US$
1.00
1 Piece
(MOQ)
New Design Roller Cone PDC Insert Drill Tricone Drill Bits
US$
100.00
1 Piece
(MOQ)
1/4
YANTAI PANDA EQUIPMENT CO., LTD.
Send Inquiry
Guaranteed Quality Hard Rock Mining with Carbide Insert TCI Rotary Roller 8 1 / 2 Inch IADC 517 Tricone Bit Rock Bit for Drilling
US$
200.00
-
15,000.00
1 Piece
(MOQ)
TCI Tengusten Carbide Inside Tricone Bit IADC517
US$
200.00
-
15,000.00
1 Piece
(MOQ)
Guaranteed Quality Insert Tricone Bit 17 1/2" Tricone Bit Water Drill Tricone Bit
US$
200.00
-
15,000.00
1 Piece
(MOQ)
IADC517, 527 Metal Sealed Bearing Tricone Drill Bit
US$
200.00
-
15,000.00
1 Piece
(MOQ)
1/4
Xiamen Sansung Mining Equipment Co., Ltd.
13 yrs
·
Trading Company
Send Inquiry
Water Well Drilling and Stone Mining Three Cone Roller TCI Insert Rock Tricone Bit
US$
1,500.00
-
3,000.00
1 Piece
(MOQ)
Sealed and Non-Sealed Open Bearing Carbide Insert TCI Mining Tricone Bit
US$
1,500.00
-
3,000.00
1 Piece
(MOQ)
Blast Hole Button Insert Tricone Roller Bit for Soft to Hard Formation in Mining
US$
1,500.00
-
3,000.00
1 Piece
(MOQ)
Carbide Insert TCI Rotary Tricone Bit for Hard Rock Mining
US$
1,500.00
-
3,000.00
1 Piece
(MOQ)
1/4
HEJIAN YINHAI ROCK BITS MANUFACTURE CO., LTD.
15 yrs
·
5.0
·
Manufacturer/Factory & Trading Company
Send Inquiry
16" Tungsten Carbide Inserts Bits Tricone Bits
US$
2,199.00
-
2,399.00
1 Piece
(MOQ)
12 1/4" IADC537 Inserts Bit Rubber Sealed Bit Tricone Drill Bit
US$
1,949.00
-
2,049.00
1 Piece
(MOQ)
7" IADC517 Chisel Inserts Tricone Bit, Rock Drill Bit, Roller Cone Bit
US$
699.00
-
769.00
1 Piece
(MOQ)
8 1/2" IADC637 Spherical Inserts Drill Tricone Bits
US$
779.00
-
849.00
1 Piece
(MOQ)
1/4
Hebei Ruishi Bits Manufacturing Co., Ltd
20 yrs
·
Manufacturer/Factory & Trading Company
Send Inquiry
Cleaning Tubing 4-7/8" API Factory IADC 537 637 Tricone Roller Bit TCI Bits Tungsten Carbide Insert Drilling Bits
US$
1.00
-
1,500.00
1 Piece
(MOQ)
IADC 715 Tungsten Carbide Insert Tricone Roller Bit 215.9 mm Oil Oilfield Well Drilling Bit 8-1/2 Inch TCI Gas Geothermy Well Drilling
US$
1.00
-
8,888.00
1 Piece
(MOQ)
9-3/4 Inch Mining Well Drilling-Tools API Tricone Roller Bit Tungsten Carbide Insert TCI Drill Bit
US$
1.00
-
8,888.00
1 Piece
(MOQ)
Ruishi Bit Brand 9-1/2 Tungsten Carbide Inserts TCI Oilfield Well Drilling Roller Cone Bit 14-3/4 Inch Milled Tooth Tricone Roller Bit 7inch Gas Steel Tooth Bit
US$
1.00
-
5,555.00
1 Piece
(MOQ)
1/4
Hejian Longyue Drill Bit Manufacture Co., Ltd.
10 yrs
·
Manufacturer/Factory & Trading Company
Send Inquiry
Factory Price IADC537 Sliding Bearing Insert Oil Well Drill TCI Tricone Bit Sizes
US$
500.00
1 Piece
(MOQ)
215.9mm Well Drilling Insert TCI Rock Roller Tricone Bit
US$
300.00
-
900.00
1 Piece
(MOQ)
12 1/4′ ′ IADC 537 TCI Drill Bit, Insert Tricone Rotary Bit, Water Well Drilling Bit, Drilling for Groundwater
US$
1,500.00
-
4,000.00
1 Piece
(MOQ)
12 1/4'' IADC 537 TCI Drill Bit/Insert Tricone Rotary Bit, Water Well Drilling Equipment, Drilling for Groundwater
US$
1,500.00
-
4,000.00
1 Piece
(MOQ)
1/4
HEBEI XINHUAFA PETROLEUM MACHINERY CO., LTD.
21 yrs
·
5.0
·
Manufacturer/Factory & Trading Company
Send Inquiry
High Quality Pilot Tricone Bit Tricone Bit Smith Insert
US$
100.00
-
3,000.00
3 Pieces
(MOQ)
8-1/2" API Tc I Tricone Bits/Button Insert Bits /Roller Cone Bits
US$
100.00
-
3,000.00
3 Pieces
(MOQ)
Factory Directly Provide Hard Rock Mining with Carbide Insert TCI Rotary Roller API 8 1/2" TCI Tricone Bit Three Cone Bit for Hard Rock Drilling Drill Bits
US$
100.00
-
3,000.00
3 Pieces
(MOQ)
6" 6 1/4" 6 1/2" 6 3/4"=150~171.5mm 3-1/2 API Reg Water Well Drilling Tricone Drill Bit
US$
100.00
-
3,000.00
3 Pieces
(MOQ)
1/4
Hongkong Eastlong Technology Co., Limited
Send Inquiry
Roller Cone Drill Bits Three Rotating Cones Tricone Bit with Large and Long Chisel-Shaped Inserts
US$
4.90
-
5.00
10 Pieces
(MOQ)
Roller Cone Drill Bits Three Rotating Cones Tricone Bit with Large Long Chisel-Shaped Inserts
US$
4.90
-
5.00
100 Pieces
(MOQ)
New Design Russian Hot Sale Roller Cone Plam PDC Insert Drill Tricone Drill Bits
US$
4.90
-
5.00
100 Pieces
(MOQ)
Tricone Drill Bit TCI Tungsten Carbide Insert Roller Cone Bit for Oil Well Hard Rock Drilling
US$
4.90
-
5.00
100 Pieces
(MOQ)
1/4
Guangzhou International Technology Co., Ltd.
5.0
Send Inquiry
Professional Drilling Bits Tricone Rotary Three Cones TCI 6-Inch Insert Tooth IADC537 Tricone Well Rock Three Wings Drilling Bit
US$
200.00
-
800.00
1 Piece
(MOQ)
Rock Roller Cone Drill Bit Rotary Three Cones Bit TCI Tricone Rock Bit 16-Inch IADC537g Insert Tricone Bit Oil and Well Drilling Bit
US$
400.00
-
3,800.00
1 Piece
(MOQ)
Ranking Tricone Drill Bit Insert Tungsten IADC 737 TCI Bit Roller Cone Bit for Sale
US$
200.00
-
17,000.00
1 Piece
(MOQ)
Rock Drill Bit 298mm TCI Tricone Bit Drilling Tool 8 1/2-Inch 216mm Tricone Bit Inserts
US$
100.00
-
1,500.00
1 Piece
(MOQ)
1/4
Hunan Hippo Drilling Tool Co., Ltd.
5.0
Send Inquiry
5 1/2" 22"Tricone Roller Bit with Tungsten Carbide Insert for Mining
US$
200.00
-
7,000.00
1 Piece
(MOQ)
Tungsten Carbide Inserts Rock Tricone Drill Bit Tool
US$
200.00
-
7,000.00
1 Piece
(MOQ)
Tricone Roller Bit with Tungsten Carbide Insert for Mining
US$
200.00
-
7,000.00
1 Piece
(MOQ)
IADC537 Rock Drilling Tools Sliding Bearing Insert Tooth Bit Tricone Drill Bit for Mining
US$
200.00
-
7,000.00
1 Piece
(MOQ)
1/4
HEFEI ROSCHEN TOOL CO., LTD.
Send Inquiry
8-1/2" IADC 637 Tricone Roller Insert Bit for Drilling
US$
500.00
-
5,000.00
1 Piece
(MOQ)
12 1/4" HDD Guide Tricone Bit with Inserts
US$
2,500.00
-
2,800.00
1 Piece
(MOQ)
8 3/4" Steel Tooth Tricone Drill Bit
US$
500.00
-
2,500.00
1 Piece
(MOQ)
17 1/2 Inch Tricone Rock Drill Bits/ Bearing Tricone Bits/ Water Well Drill Bit
US$
200.00
-
5,000.00
1 Piece
(MOQ)
1/4
PUTIAN QIDELI ENGINEERING EQUIPMENT CO., LTD.
Send Inquiry
Tungsten Carbide Inserts Bit 200mm Tricone Bit/ 7 7/8" Roller Cone Bit for Water/Oil/Gas Well Drilling Tools
US$
1,200.00
1 Piece
(MOQ)
12 1/4" Tungsten Carbide Inserts Bit 311 mm Tricone Bit Reg
US$
3,000.00
1 Piece
(MOQ)
Tungsten Carbide Inserts Bit 375 mm Reg Tricone Bit / 14 3/4" Roller Cone Bit for Water/Oil/Gas Well Drilling Tools
US$
3,000.00
1 Piece
(MOQ)
5 1/2" (140mm) IADC: 637 TCI Drill Bit/Rock Bit/Tcicone Bit for Mining Drilling
US$
495.00
1 Piece
(MOQ)
1/4
Cangzhou JW Petroleum Machinery Co., Ltd.
Send Inquiry
TCI Insert Teeth Tricone Button Rock Drill Bit
US$
512.00
-
2,212.00
1 Piece
(MOQ)
9 7/8'' TCI Insert Tricone Rotary Drill Bit for Hard Rock
US$
500.00
-
900.00
1 Piece
(MOQ)
8 3/4'' Deep Well Insert Tooth Tricone Rock Bit Rotary Bit
US$
1,150.00
1 Piece
(MOQ)
IADC537 Oil Well 9 1/2" Tricone Core Drilling Bits
US$
1,920.00
1 Piece
(MOQ)
1/4
Shandong Better Drilling Machinery Co., Ltd.
7 yrs
·
5.0
·
Manufacturer/Factory & Trading Company
Send Inquiry
TCI Insert Tricone Drill Bit High Precision for Geological Exploration
US$
120.00
-
150.00
1 Piece
(MOQ)
Sealed Lubricated Tricone Drill Bit TCI Insert for High-Pressure Drilling
US$
120.00
-
150.00
1 Piece
(MOQ)
High-Performance Tricone Bit for Gas Well Applications
US$
200.00
-
500.00
1 Set
(MOQ)
Advanced Tricone Bit for High-Performance Gas Well Drilling
US$
200.00
-
500.00
1 Set
(MOQ)
1/4
Dongying Lake Petroleum Technology Co., Ltd.
15 yrs
·
5.0
·
Trading Company
Send Inquiry
IADC535 17.5in Insert Teeth Tricone Drill Bit for Drilling
US$
600.00
1 Piece
(MOQ)
TCI Tricone Bit/Roller Cone Bit/Rock Bit for Drilling
US$
46.00
-
50.00
1 Piece
(MOQ)
Sv Series 9-1/2" Drill Bit Roller Cone Drill Bit
US$
2,000.00
-
100,000.00
1 Piece
(MOQ)
7-1 8-1/2" Metrix Body Roller Cone Drill Bit Roller Bit
US$
2,000.00
-
100,000.00
1 Piece
(MOQ)
1/4
Putian Firip Mining&Machinery Co., Ltd.
3 yrs
·
5.0
·
Manufacturer/Factory
Send Inquiry
17 1/2" IADC 537 TCI Tricone Drill Bit for Water Well & Oil Gas Drilling - Tungsten Carbide Insert Roller Cone Bit
US$
500.00
-
5,000.00
1 Piece
(MOQ)
26" TCI Tricone Drill Bit for Large Diameter Well Drilling
US$
500.00
-
5,000.00
1 Piece
(MOQ)
13 1/8" Steel Tooth Tricone Bit for Deep Well Drilling
US$
500.00
-
5,000.00
1 Piece
(MOQ)
12 1/4" Steel Tooth Tricone Bit for Well Drilling
US$
500.00
-
5,000.00
1 Piece
(MOQ)
1/4
Changsha DTH Drill Construction Machinery Co., Ltd.
5.0
Send Inquiry
Premium 6'' Tricone Drill Bits with Tungsten Carbide Inserts
US$
450.00
-
545.00
1 Piece
(MOQ)
Durable 8 1/2'' Tricone Drill Bits for Efficient Water Drilling
US$
150.00
-
990.00
1 Piece
(MOQ)
Premium 22-Inch TCI Tricone Bit for Heavy-Duty Rock Drilling
US$
99.00
-
4,980.00
1 Piece
(MOQ)
High-Performance Alloy Steel Tricone Drill Bit for Coal Applications
US$
440.00
1 Piece
(MOQ)
1/4
Shandong Yacheng Petroleum Technology Co., Ltd.
11 yrs
·
Trading Company
Send Inquiry
IADC537 Tungsten Carbide Insert Tricone Bit 12 1/4 Inch 6 5/8 Reg
US$
500.00
-
4,500.00
1 Piece
(MOQ)
API Standard Oilfield Long Worklife Drill Rig Use Tricone Drill Bit for Sale
US$
200.00
-
600,000.00
1 Set
(MOQ)
API Oilfield 12 1/4 Inch IADC 637 TCI Tricone Rock Drill Bit
US$
700.00
-
3,000.00
1 Piece
(MOQ)
API 6 1/2 IADC517 537 API TCI Tricone Rock Bits
US$
600.00
-
4,500.00
1 Piece
(MOQ)
1/4
Outewei (Jiangsu) Machinery Technology Co., Ltd.
11 yrs
·
Manufacturer/Factory & Trading Company
Send Inquiry
Tricone Drill Bits That Cutting Sructure Have Premium Tungsten Carbide Insert
US$
3,200.00
-
3,300.00
10 Pieces
(MOQ)
Premium Tricone Drill Bits for Fast and Efficient Rock Drilling
US$
2,000.00
-
2,600.00
100 Pieces
(MOQ)
7 1/2" 7 7/8" ~9 1/2" 9 5/8" 9 7/8" API Tricone Bit/ Rock Drill Bit/ Roller Cone Bit for Water/Oil/Gas Well Drilling
US$
3,200.00
-
3,300.00
10 Pieces
(MOQ)
Customized High-Performance Steel Tricone Drill Bit with Innovative Wing Design
US$
2,000.00
-
2,600.00
100 Pieces
(MOQ)
1/4
Luoyang Shandike Mechanical Equipment Co., Ltd.
Send Inquiry
Drilling Tools Oil Drill Bit Price Mining Carbide Insert Well Tricone Bit Drill Bit for Rock Bearing Tungsten Carbide Tricone Rock Drill Bit
US$
900.00
-
1,350.00
2 Pieces
(MOQ)
Drill Tungsten Carbide R32 Rock Drilling Tools Mining Carbide Threaded Button Bits
US$
55.00
-
59.00
5 Pieces
(MOQ)
Water Well Drilling Air Hammer Drill Tungsten Carbide Hard Rock Roller Tricone Drill Bit for Rock
US$
900.00
-
1,350.00
2 Pieces
(MOQ)
China Factory Supply Good Oil Drill Bit Price Air Hammer Drill Tungsten Carbide High Air Pressure Hammer Mining Rock DTH Drill Bits for Water Well
US$
40.00
-
580.00
1 Piece
(MOQ)
1/4
Changsha Sollroc Engineering Equipments Co., Ltd.
Send Inquiry
IADC537 Tugsten Carbide Insert TCI Tricone Roller Bits for Well Drilling
US$
1,000.00
-
2,000.00
1 Piece
(MOQ)
229mm Best Quality Tricone Bits for Well Drilling
US$
1,100.00
-
2,000.00
1 Piece
(MOQ)
12 1/4" 311mm IADC437 TCI Tricone Bit
US$
1,500.00
-
2,500.00
1 Piece
(MOQ)
IADC/TCI Tungsten Carbide / Steel Tooth /Mill Tooth Tricone Roller Bit for Oil/Well Drilling/ Coal Mining
US$
800.00
-
1,000.00
1 Piece
(MOQ)
1/4
Dezhou Drillstar Co., Ltd
13 yrs
·
Manufacturer/Factory & Trading Company
Send Inquiry
Tricone Drill Bit TCI Tungsten Carbide Insert Roller Cone Bit for Oil Well Hard Rock Drilling
US$
18.00
10 Pieces
(MOQ)
Mining Well Tricone Carbide Bits Three Cone Trico
US$
69.00
10 Pieces
(MOQ)
High-Performance Oil Drilling Bits Are From Drillstar, Factory Direct Sales.
US$
10.00
10 Pieces
(MOQ)
Durable Oil and Gas Industry Drill Bit for Efficient Drilling
US$
10.00
10 Pieces
(MOQ)
1/4
Zhejiang Sanrock Supply Management Co., Ltd.
Send Inquiry
TCI Tricone Drill Bit Sliding Bearing Insert Tooth Oil Well Tricone Bit
US$
460.00
-
500.00
1 Set
(MOQ)
Competitive Price DTH Hammer Bit Mining Machinery Parts DTH Button Drill Bit
US$
135.00
-
147.00
5 Pieces
(MOQ)
Tricone Roller Bit Steel Milled Tooth Tricone Drill Bit for Oil Well
US$
460.00
-
500.00
1 Set
(MOQ)
TCI Tricone Roller Drill Bit Oilfield Rock Drilling Tools Tricone Bit
US$
460.00
-
500.00
1 Set
(MOQ)
1/4
Changsha Heijingang Industrial Co., Ltd.
27 yrs
·
Manufacturer/Factory & Trading Company
Send Inquiry
IADC745 12 1/4 Inch 311mm Mining Tricone Bit
US$
999.00
-
1,200.00
1 Piece
(MOQ)
7-7/8" Rotary Tricone Bit Mining Blasthole Drilling
US$
999.00
-
1,200.00
1 Piece
(MOQ)
7 7/8" Rotary Tricone Bit Mining Blasthole Drilling
US$
888.00
-
1,100.00
1 Piece
(MOQ)
12 1/4" Rotary Tricone Bit Mining Blasthole Drilling
US$
999.00
-
1,200.00
1 Piece
(MOQ)
1/4
1
6
Hot Products
Water Drilling
Water Well Drilling
Drill Bits
Button Bit
Rock Bit
Water Well Drilling Bits
Rock Drilling Bit
Steel Tooth Bits
Related Manufacturers & Supplier
Roller Bit Factories
Used Tricone Bits Factories
New Tricone Bits Factories
Tricone Bit Factories
Tungsten Carbide Insert Bit Manufacturers
Used Tricone Drill Bits Manufacturers
Tricone Drill Bit Manufacturers
Cone Bits Manufacturers