This long router bits is a home made or custom made cutters for big fast foam block machining. Widely used used with form mould making cnc router for cutting polystyrene foam, EPS, Styrofoam, etc. Long Foam Cutting Router Bits Features: 1, High Speed Steel (HSS) hardness: HRC 61-64.5° 2, Sharp spiral blade for clear smooth finishing 3, Extended Reach for deep carving and milling 4, Foam cutter size could be customized Diameter: 6mm, 8mm, 10mm, 12mm, 16mm, 20mm, 25mm, 30mm, 32mm, 40mm, etc.