100 Bushings for hole punched by 709 for 7/8 inch (22.2 mm) diameter hole. Triple lock design holds bushing securely. Locks securely into metal studs from 24 gauge to 12 gauge (0.6 mm to 2.5 mm). Helps protect wire insulation from sharp edges of metal studs. Makes pulling smooth and easy by preventing hang-ups of cable on raw metal edges.