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Light mace
Attack bonus if proficient +2
Weapon die ([W]) 1d6
Type melee
Handedness one-handed
Proficiency category simple
Weapon group
Weapon properties off-hand, small
Price 3 gp
Weight 2 lb.

A light mace is a simple one-handed melee weapon in the mace weapon group.[MME:21]

A light mace is an off-hand weapon. A character can use a light mace to make attacks even while holding another one-handed weapon in the other hand, and can use the other one-handed weapon to make attacks even if it isn't an off-hand weapon. A light mace is also a small weapon.

Ardents, artificers, avengers, barbarians, bards, battleminds, clerics, druids, fighters, invokers, paladins, psions, rangers, runepriests, seekers, shamans, sorcerers, swordmages, vampires, wardens, warlocks, and warlords are proficient with all simple melee weapons, including the light mace. Assassins are proficient with one-handed simple melee weapons, including the light mace.

Other classes do not have proficiency with the light mace as a class trait, but any character can become proficient by taking a Weapon Proficiency feat.