Functions of wind hole: Excluding scraps Reducing noise Cooling purposes Suitable for cutting hard and brittle materials Sintered Saw Blade with Multi-Function Windholes Item Number Outer Diameter Hole Diameter Segment Dimension Core Thickness Segment Number INCHES Metric (MM) INCHES Metric (MM) Hc0103006 9" 230 20/7/8" 25.4/30/50 1.8*7.2*34 1.8 18 Hc0103007 10" 250 7/8"/1" 25.4/30/50 3.0*7.5*37 2.2 18 Hc0103008 12" 300 1"/2" 25.4/30/50 3.2*7.5*35 2.2 22