The energy grenade is a crystalline egg-like device encasing some form of energy like positive energy or negative energy. Positive energy grenades are commonly referred to as Pos-Grenades. Those with negative energy are commonly called Howlers or NEGs.
The area of effect for the energy grenade is a 10' radius (Reflex DC16 for half damage). Energy grenades are 6" diameter, approximately 2" thick in the center and narrowing to 1/4" at the edge, and weigh four pounds.