Professional metal foam gun.
The adapter won't get stuck as long as 30-day down-time.
Durable gun.

Professional metal 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. 

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).