Without a doubt, whether the metric is net margin or balance sheet, the most profitable construction companies are full service type, providing“design, engineering, project management, construction and procurement” in the heavy industrial and civil sectors. You can contact Wuxi Henderchan Industrial Co Ltd,Zhongshan Safe and Firm Hardware Products Co., Ltd.,Guangdong Yijun Precision Technology Co., Ltd.,Zhaoqing Keyi Metal Manufacturing Co., Ltd.,EC Hardware Co., Ltd. via the red button for more infomation.