Starrett Bi-metal holesaws are constructed of hardened, heat and abrasion resisting high speed steel teeth with a tough alloy body and cap.This gives them exceptional strength, durability and shatter resistance for user safety.They will cut any wood, metal or plastic in either a hand-held drill or a drill press.Max. Cutting Depth. 38 mm.Size.108 mm 4 1/4 inchArbors to suit (available separately)Code Holesaw Size ShankSTRA1 14-30 mm 11/32in (8.75mm) HexSTRA4 14-30 mm 1/4 in (6.50mm) RoundSTRA2 32-152 mm 7/16 in (11.00mm) HexSTRA10 32-152 mm 11/32 in (8.75mm) Hex