Diamond brazed drill bit using special technology, vacuum brazed diamond, diamond and the substrate to ensure a solid, a blade because of its high chip removal space, ensure maximum sharpness. Can be used wet and dry, add water, a better effect. Long life, high efficiency, is an excellent alternative to electroplating. Connection: Straight shank drill and threaded shank. M14 and 5/8"-11 thread. Particle size: coarse, medium and fine.