The Pulse grenade was a device, that was used as a hand-held explosive during the Great Race War. It was secretly manufactured prior to the war, and then distributed at the onset of the Battle of Midgård.
Shape-wise, the pulse grenades were roughly hexagonal in shape. The explosive was primed by pulling the two halves of the chassis away from each other. Three quick 'beeps' after that would indicate an imminent explosion.  Due to a complex design, the original grenade models were only used exclusively by the Feline Matriarchate loyalists. Soon however, the other competing factons would begin producing their own variations.