Heavy Duty, Hammer Tacker, Steel Construction, High Carbon Steel Working Parts, Chrome Finish, Non Slip Grip Handle, Narrow Crown, Auto Feed & Drive Staples Lightweight, Uses 1250 Pack T-50 1/4" TV #137-190, 5/16" TV #137-364, 3/8" TV #137-406 & 1/2" TV #139-337 Narrow Crown Staples.