Master Mechanic, Heavy Duty Staple Gun, All Steel Construction, Bottom Loading Magazine, Easy Drop In Loading No Plunger To Lose, Compatible With T50 Arrow Staples Sizes: 1/4" (TV# 137190), 5/16" (TV# 137364), 3/8" (TV# 137406), 1/2" (TV# 139337) & 9/16" (TV# 353562).