1. CONSTRUCTION GRADE Hole Saw Cutting Diameter: 220mm/8.58'; Opening Depth: 25mm/0.98'; Handle Diameter: 10mm/0.39'; Hole Saw is made of HSS M42 high speed steel, impact resistance, wear resistance. With higher hardness, higher toughness and stronger resistance; Well made, sharp, hard, lasting. Comes with drill bit hardware. 2. HIGHPERfORMANCE MATERIALS Hole saws is made of M42 highspeed steel and BI metal, with higher hardness higher toughness, higher cutting strength and stronger wear resistance. 3. EFFICIENT SMOOTH CUTTING Highquality bimetal and the cutting performance of HSS teeth combines with Nonbinding clean edge design ensures smooth and clean cutting of the hole saw blade. 4. WIDELY USED Hole saws can cut 8.58' diameter holes in wood, plywood, plastic, drywall, soft plaster, cornhole boards and thin metals. In addition to punching cans or recessed lights, punching saws are also suitable for home projects on air ducts, speakers, ceiling lamps, etc.