... carbide tip to reduce breakout. Available in seven sizes: 1/8" (3mm), 5/32"(4mm),3/16" (5mm ... (6mm), 5/16" (8mm), 3/8" (10mm) and 1/2" (12mm), these spear bits provide smooth, accurate drilling in ... because of you, our customer. Satisfying you is our #1 concern. We have been in the business of satisfying customers ... goal - so don't hesitate to contact us! export high quality 1/2" Glass and Tile Drill Bit