Heavy Duty, Staple Gun Tacker, All Steel Construction, Steel Working Parts, Chrome Finish ,Jam Proof Mechanism, Refill Window Double Leverage Operation, Uses Heavy Duty T50 Staples 1/4" TV #137-190, 5/16" TV #137-364, 3/8" TV #137-406, 1/2" TV #139-337, 9/16" TV #353-562 & 17/32" CT TV #140-053 Staples Narrow Crown.