Heavy Duty Center Punch Dimensions : 6" Long x 11/16" Diameter Point Diameter : 0.015 Inches (0.4 mm ) Medium Duty Center Punch Dimensions : 5" Long x 9/16" Diameter Point Diameter : 0.012 Inches (0.3 mm ) . Body is made from Alloy steel grade of EN8D and EN31 is used for Quill/ Point Center DELIVERS A HIGH IMPACT STRIKE - One handed spring-loaded impact operation, no hammer require AUTOMATIC PUNCH DEPTH - center punch can be set for repetitive work. Ideal for punching, marking, scribing to drill, nail and screw holes. Heavy Duty Center Punch Dimensions : 6" Long x 11/16" Diameter Point Diameter : 0.015 Inches (0.4 mm ) Medium Duty Center Punch Dimensions : 5" Long x 9/16" Diameter Point Diameter : 0.012 Inches (0.3 mm ) . DELIVERS A HIGH IMPACT STRIKE - One handed spring-loaded impact operation, no hammer required ADJUSTABLE SPRING TENSION - Adjustable spring tension cap for light or heavy strokes and marking AUTOMATIC PUNCH DEPTH - center punch can be set for repetitive work. Ideal for punching, marking, scribing to drill, nail and screw holes.