economical metal 1-c PU foam gun

Light gun: The worker won't feel tired after long works.
Lazy gun: The worker does not need to clean the guns with solvent after use, due to the sticking-proof features of our guns.

30 days later when the worker unlocks the needle, the gun works as well as before.  The foam inside the gun won't get stuck (without taking off the foam cans away from the adapter).