Montana Brand 1/4 in. Dia. Alloy Steel Drill Bit 1 pc. Montana Brand Diamond Tile drill bits provide outstanding performance in ceramic, porcelain, granite, slate, marble, glass and most all hard surface materials. Drill holes for water supply lines, drains, electrical/wiring, towel bars and fixture installations. Also great for glass and decorative crafts. Features 10X Faster drilling than standard glass and tile drill bits 15X Longer life versus carbide tip spade drill bits 40+ Holes per drill bit Diamond sintered cutting edge drills clean, round holes Segmented cutting edge design for improved irrigation and material evacuation USA SHIPPING estimates delivery times and we work to get your item to you as quickly as possible and within those times, but please know it may take slightly longer than the estimate.