Bit rings are used as a shaft collar on machinery and can be used on drill bits or point drills or any type of bit to prevent excessive drill bit penetration and for any jobs that uses a bit and needs precision. Features - Color: Silver. - Material: Stainless steel. - Size: 1.70X1.00X0.80cm/0.67X0.39X0.31 inch. - Specification: 3, 4, 5, 6, 7, 8, 9, 10mm. - Assorted sizes: 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm. - This drill bit depth stop collar is widely used for woodworking drill bit consistent drilling. - This depth stop collar can be locked anywhere along the bit, widely used for high carbon steel drills. - Mainly for fixing the drill bit, limited the depth of drill holes, make depth of the hole consistent. - Fine workmanship and creative appearance ensure its popularity and practicality. Package list: 8 x Drill Bit Collars