JINYU describe: Core box bits are designed for reeding, grooving, sign making and general round nose grooving. It is especially effective when slotting flat surfaces. Steel drill bits for the high demands of woodworking and hardware. Industrial quality. Tungsten carbide cutters. Specification: Shank diameter: 8mm Different monitors may have different colors, please understand Please allow 1mm error due to manual testing, thanks Shipment Quantity: 1 piece Package Contents: Only the above package content, other products are not included. Size: 16*41.5mm (Reminder: The size is measured by hand, please allow 1-2cm measurement error) color: red (Due to different monitors and lighting effects, the actual color of the product may be slightly different from the picture color.)