"The Locus is a timed-fuse fragmentation explosive that is highly effective against Dropsuit armour."
The Locus Grenade is the standard issue grenade, and the only one with a militia variant.
The Locus Grenade has a 5 second fuze; like all grenades, it can be "cooked" so it will explode sooner after being thrown (beware, as it can explode in your hand). The clicking that the grenade makes to denote the explosion countdown reportedly sounds like a chicken clucking.
As an Explosive Weapon, the Locus Grenade has a +20% damage bonus to armour, and a -20% damage penalty to shields.