These grenades are not really "explosives", but devices that create a small worm hole where they impact.
The worm hole is only about 6 ft. across, but it will consume anything, including the ground, within a 3 meter radius. The worm hole can olny sustain itself for about 3 seconds, however.
Negator grenades are very unstable, as they contain an enourmous amount of energy, and are highly illegal. They are only occasionally used by the GD.
When the button in the center is pressed, energy is pushed into the capacitors that power the miniature particle accelerator unit, and a timer (5 sec.) starts. The grenade is now armed. To unarm, simply push the button again.
Another version of these grenades is dropped from aircraft. This version is the same in all respects, except instead of a timer, they explode on impact.