16 Pieces of woodworking bit depth stop collar rings in 8 different sizes, meet your various needs, suitable for lots of twist bits, multi-functional bits, woodworking bits, etc.Mainly used for adjusting and fixing limit drilling depth on the drill bit, perfect for precise drilling, which is suitable for production and repeated drilling work, suitable for drilling wood or walls.How to UseChoose the appropriate size drill bit and stop collarSlide the stop collar over the bitSet the required depth with a ruler or depth gaugeTighten the screw of the stop collarSurface treatment: Blackening treatmentInternal Diameter : 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 16mmPackage Included:2 x 3mm Drill Limited Ring2 x 4mm Drill Limited Ring2 x 5mm Drill Limited Ring2 x 6mm Drill Limited Ring2 x 8mm Drill Limited Ring2 x 10mm Drill Limited Ring2 x 12mm Drill Limited Ring2 x 16mm Drill Limited Ring2 x Hex WrenchColour:blackMaterial:carbon steelPackage Contents:1 set x 5/8 shaftOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.