Fangrui Product Details [sturdy, , Long Service Life]the 15-piece Hole Saw Is Made Of Diamond-in-one Steel, Sturdy And . The Adopts High Anti- Electroplating Process And The Top Is Thickened With Diamond Coating To Provide Excellent Cutting Strength And Achieve High-precision And Smooth Cutting. Reducing The Drilling Speed And Pressure And Increasing The Use Of Water Lubrication Greatly Extend The Service Life. [strong Suction, Precise Positioning] The Upgraded Double Suction Cup Design Provides More Powerful Suction Than A Single Suction Cup. Warm Tips: 1. Keep Ceramic Tiles, Glass, Marble And Other Surfaces Clean And Dust-free. 2. Try To Expel The Air In The Suction Cup Before Pulling Down The Handle. [easy To Use, Just 4 Steps! ] Step 1: Clean The And Mark The Drilling Locations. : Place The Hole Saw Into The Positioner And Adjust The Position Of The Hole. Step 3: The Double Suction Cup Positioning System Of The Positioner And Fix The Hole Saw By Adjusting The Positioning Shaft Wheel. Step 4: Complete The Drilling Work Under