Avengers 40mm Airsoft Gas Grenade Shell
(Model: 55rd Multi-Purpose / Red Polished / Single Shell)

"I got a 3 pack of the 60 round shower shells. They all came perfectly operational. I would recommend unscrewing the gas inlet and oiling that seal, it doesn't seem to have any oil there from the factory.

Pros:
Plenty of power with 150 psi heavy gas.
People say they work with co2.
Easy to reset, haven't had any issues yet.
No leaks! (yet)
You can unscrew the actual shower shell part and screw in a 3D printed taginn shell barrel.
All of the retaining O-rings for holding in BBs do their job well, I haven't had any BBs come out, even with some violent shaking.

Cons:
The matte paint is easy to scratch.
Again, there was no oil around the gas inlet.

We'll see about longevity, but they're a pretty solid shell.

"Fun little addition to my airsoft collection and works in pretty much all my Grenades Launchers.

Pros:
Gives off a nice loud pop when fired.
Easy to reset.
Shower's targets in BB's galore.

Con:
Don't aim down or else all the BB's will fall out.
Prone to misfiring (I had this happen to me once, BB's went everywhere.)

"Shell works good! Reliable, hasn’t stopped working yet!