Feature:1. Adjustable Counterbore: Adjustable length of the counterborn,with fixing screw,use the attached hex key remove the screw and adjust the length of the counterbore.2. Premium Quality: The drill bit made of steel alloy,more hardness,provide fast cutting and strong force.3. Efficient Work: Smooth counterbore drilled to save you time and labor. The surface of the workpiece will be perfectly embedded with screw cap.4. Compatible with: Applied with drilling rig,bench drill,hand drill and charging drill.5. Use Tip: Vertical to avoid the drill bit from bending or breaking.Specification:Features:Adjustable Counterbore: Adjustable length of the counterborn,with fixing screw,use the attached hex key remove the screw and adjust the length of the counterbore.Premium Quality: The drill bit made of steel alloy,more hardness,provide fast cutting and strong force.Efficient Work: Smooth counterbore drilled to save you time and labor. The surface of the workpiece will be perfectly embedded with screw cap.Compatible with: Applied with drilling rig,bench drill,hand drill and charging drill.Use Tip: Vertical to avoid the drill bit from bending or breaking.Specifications:Material: Steel Alloy Size: 8*2.8, 8*3, 8*3.2, 8*3.5, 8*4mmItem Weight: 98g / 3.46ozPackage Weight: 107g / 3.77ozPackage Size: 100*50*50mm / 3.94*1.97*1.97inPackage List:5 * Drill Bit5 * Hex KeyPackage List:5 * Drill Bit5 * Hex Key