an anyone help me identify this reusable grenade?

[NitroJoe]

Couldn't think of a better section to post this in.

Does anyone have any info on this grenade? Does it have an adjustable delay? Any comments or suggestions?

I haven't tested it yet, but I imagine any O-rings will be knackered and the valve/pin doesn't pop up very easily (only seems to when I unscrew the cap) I've left it soaking in silicone spray to ease it up.

I guess as it's gas, it doesn't make a loud bang? I want to test it, but not if the neighbours think I've taken up bomb making as a hobby!

Thanks in advance for any help