Description: Material: Marble Opener is made of high quality adamas material,high hardness. slotted design:The tool head is sharp,The opening resistance issmall ,which is good for chip removal,fast cutting ,the holes are neat and free of burrs. Chip removal design:The drill tail had a design.Make the clamping more stable.hole opener is Suitable for hand drills ,bench drills ,etc Application:It can be used for drilling hard and brittle materials such as marble, ceramics, cement, and tiles. Note:Since the hole opener does not have a central positioning drill bit must first tilt the angle 45 to contact the marble slowly. Size Chart: Hole diameter:4cm/1.57inch Hole diameter:4.5cm/1.77inch Hole diameter:5cm/1.97inch Hole diameter:5.5cm/2.17inch Hole diameter:6cm/2.36inch Hole diameter:6.5cm/2.56inch Hole diameter:7cm/2.76inch Hole diameter:7.5cm/2.95inch Hole diameter:4.2cm/1.65inch Package Includes: 1 Marble Opener Note: Please allow slightly errors due to manual measurement and different monitors.