Descriptions:1.Plated surface treatment for great anti-rust.2.Widely used in woodworking.Specifications:Color:orangeMaterial: alloyDrilling bit diameter:3.5mmRod diameter:8mm Features:1. Special designed steel counter sleeve countersinks or counter bores pilot hole.2. Adjustable counter sleeve depth with Allen wrench3. Standard hex shank, quickly changing and compatible.4. Drill and countersink for wood screws without changing bits.5. Drilling length can be adjusted for various length screws simply by loosening and tightening the setscrew.