Premium Material Carbide drill bits are built for longevity and will stay sharper much longer than you are with a typical steel drill bit.Superiori Superior Performance Spearhead Design, This carbide drill bit is sharp, easy to locate, stable drilling, fast speed, does not break the edge, neat opening, smooth. And the 3-stage shank ensures that it is held securely without slipping or scratching, it will not damage the glaze of the tiles. penetrate various materials (tiles, concrete, brick wall, glass, mirrors, plastic and wooden walls).U-slot design type U-slot design with fast removal of dust from drilling, triangular handle design, more stable operation.7 sizes with 7 different sizes: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 3-point shank, these glass drill bits are very suitable for various drilling activities, high precision drilling. Rotating wire design, easier drilling and chip removal.