Features: Drill Stop Bit Collar Set will quickly and easily help you drill hole to exact depths They are for production work and repeated drilling by positively locking anywhere along the bit. Includes:3mm/0.118in,4mm/0.157in,5mm/0.197in,6mm/0.236in,8mm/0.315in,10mm/0.394in,12mm/0.472in,16 mm/0.63in; Carbon Steel features good corrosion resistance and heat resistance; Packing List: 8x Stop Collar,1x Wrench; Specifications: Material:Carbon Steel Includes:3mm/0.118in,4mm/0.157in,5mm/0.197in,6mm/0.236in,8mm/0.315in,10mm/0.394in,12mm/0.472in,16 mm/0.63in; M3: Inner diameter is about 3.2mm/0.126in, outer diameter is about 9.8mm/0.386in, thickness is about 3.5mm/0.138in, and height is about 8mm/0.315in. M4: Inner diameter is about 4.2mm/0.165in, outer diameter is about 9.8mm/0.386in, thickness is about 3mm/0.118in, and height is about 8mm/0.315in. M5: Inner diameter approx. 5.2mm/0.205in, outer diameter approx. 11.8mm/0.465in, thickness approx. 3.4mm/0.134in, height approx. 8mm/0.315in. M6: Inner diameter: approx. 6.2mm/0.244in, outer diameter: approx. 11.8mm/0.465in, thickness: approx. 3mm/0.118in, height: approx. 8mm/0.315in. M8: Inner diameter approx. 8.3mm/0.327in, outer diameter approx.16mm/0.63in, thickness approx. 3.9mm/0.154in, height approx. 8mm/0.315in. M10: Inner diameter approx. 10.3mm/0.406in, outer diameter approx.18mm/0.709in, thickness approx. 3.8mm/0.15in, height approx. 8mm/0.315in. M12: Inner diameter approx. 12.2mm/0.48in, outer diameter approx. 20mm/0.787in, thickness approx.3.9mm/0.154in, height approx. 8mm/0.315in. M16: Inner diameter: approx. 16.2mm/0.638in, outer diameter: approx. 24mm/0.945in, thickness: approx. 4mm/0.157in, height: approx. 8mm/0.315in. Note: Please allow 1-2cm errors due to manual measurement,please make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1set Drill Bit Depth Stop Collar Rings(8pcs) 1xAllen Wrench