Pros:
Secondary attack for a shock effect that hits multiple enemies (Uses full clip and does 100 damage, -20% damage after each person it hits, meaning first person hit by shock takes 100 damage, next takes 80, then 66, etc.)
+25% reserve ammo
+50% damage to buildings

Cons:
-25% damage to players
-85% ammo per clip (2 instead of 12, or -66% ammo if this is primary weapon)

I assume this is a secondary weapon.