A thicken diamond coating on the tops offers superior cutting strength for maximum drilling outcomes SHARP & SMOOTH CUT The diamond hole saw creates a high precision, smooth cut with no broken edges. Excellent for making clean and accurate hole SATISFIED SIZE Cutting hole diameter : 8mm / 0.3 inch, length: 5cm /2inch. Super drill bits you can drill where you want to drill your hole and use it as a "guide" to start the hole OPERATION Start drill at 45 degrees to surface and align to 90 degrees as hole forms. Reduced drill speeds, low drill pressure,and water is required to cool down the drill when using them, extend drill bit life considerably APPLICATION Hole saws perfect for drilling glass, tile, porcelain tile, ceramic tile, brick, blocks jars, mable, light stone How to Use Tile Hole Saw Drill Correctly: Use pen to mark start of hole, and keep wet with water or coolant. Angle drill 45 degrees to start hole, and being drilling at low speeds. Angle drill to vertical position once the hole has started. Minimum pressure. Slow speed down for exit hole or drill from the other side to prevent breakthrough. Colour:Silver Material:Electroplated diamond Size:50 x 8mm Package Contents: 50 * Diamond Coated Drill Bit Note: Electroplated diamond coating will wear off if the tool gets too hot. Never let your drill bit run dry. Please keep adding water when the diamond drill bits are working on the glass or ceramics. Only the above package content, other products are not included. Note: Light 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.