1、Hole Saw Drill Set: Including 6pcs hole openers and 2pcs positioning center drills, with different specifications, which can meet more use requirements. 2、Sawtooth Design: The top sawtooth of these hole saws, high accuracy high frequency welding, ensure incisive cutter teeth and fast drilling speed. 3、Fast Chip Removal: These hole openers are equipped with multiple chip slots, fast in drilling and not easy to block, and suitable for drilling various hard stones. 4、High Speed Steel: The hole saw is made of high speed steel, with high temperature quenching, small incision resistance, neat openings, non fragile edges. 5、Easy Operation: The drilling shall be continued after the central drill is used for positioning, so as to prevent the drilling deviation, stable and reliable.