For: Airsoft Innovations Tornado Impact Grenade (Black)Product Information:
I ordered two of these, one of which failed after about 2 uses and one that has yet to let me down.
I was meticulous in maintaining/lubricating each one, but the first just will not retain O-rings for a reason I have yet to understand. I have tried multiple different sizes and brands to no avail.
The second replica, however, has been flawless, and performed beyond my pessimistic expectations. I am a big fan of Airsoft Innovations and am sure the first model was simply a lemon.
I hope your luck is better than mine!
Protip - I wrapped pink duct tape around the sides of mine and marked my callsign/team affiliation on it with a sharpie. Makes it easier for me to find, or for others to return!
Also, I put a rubber band through the loop of the pin and tied it off just below the black cap to keep from losing the pin itself.
There are always factory errors that you should be wary of.