... core drill bit 1.OEM product,competitive price 2.for stone &granite 3.good quality,fast drilling speed 3mm/min Diamond ... Core Drill Bit for stone1.OEM product,competitive price2.drilling glass, ceramic, marble and granite stone3.good quality,fast drilling ... speed 30mm/minapplication:1.for drilling glass, concrete,ceramic, marble and granite stone,concrete and asphalt etc 2.Laser welded ...