PRECISE POSITIONING: No displacement, sawdust be automatically discharged from top of hole on both sides, drill bit not be blocked. AUTOMATICAL DISCHARGE: Sawdust be automatically discharged from the top of the holes on both sides, without drill blocked. Never miss the center of the hole again, references from the hinge bevels. EASY TO REPLACE: Different hardness wood, need different centering drill, you just need take the screw apart and replace the drill. EASY TO INSTALL: design and perfect punch effect. Applicable for the installation of the door hinge. Easy to use and install, change bits fast which one-handed load and release. Feature:A. Suitable for most electric drills;B.Efficient and accurate positioning;C. upgrade 135 degree inclined blade drill bit How to use? 1.Prepare the center drill bit and hex key. 2.Rotating the hex key. 3.Grab the top of the bit and unscrew the shell (just like twist the lid off the drink) . 4.If you need replace the drill bit, just need remove the broken bit and install the replacement bit. Specifications: Type: Core Drill Bit colour: silver Material: high-speed steel size: 5/64inch, 7/64inch, 9/64inch, 9/64inch, 11/64inch Package Contents: 4*Hinge Drill Bit 1*Hex Key Warm Tips Use low speed when drilling (usually keep in 2000r/min - 3000r/min). Too fast speed off center, break the bit or jammed. When drilling the hole, please adjust according to the hardness of the wood. If the wood is soft, you can choose the smaller center drill bit. If the wood is hard, you can choose the corresponding or bigger one. If you can't get the center drill bit out after drilling, use the hex key to separate the drill bit. Only 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.