Professional 1-c PU foam gun
All visible parts (except handle) are Teflon coated, Teflon nonreturn ball.

Light gun: The worker won't feel tired after long works.
Lazy gun: The worker does not need to clean the guns with solventafter use.
30 days later when the worker unlocks the needle, the gun works aswell as before. The foam inside the gun won't get stuck (withouttaking off the foam cans away from the adapter).