Not long ago I posted some news about the Zoxna Airsoft GM2 IMPACT grenade.
When I posted I stated I’d hunt for some more information. A quick reply from Zoxna Airsoft today included a link to a new video from them that shows the operation of the device. The video is cut quickly and the BB filling is reduced to a quick montage, so I get the impression that takes time!
From what I can see the ‘impact’ part of the product name relates to it discharging upon impact rather than with a time delay: