... in seven sizes: 1/8" (3mm), 5/32"(4mm),3/16" (5mm), 1/4" (6mm), 5/16" (8mm), 3/8" (10mm) and 1/2" (12mm), these ... excellent customer serviceAll emails will be answered within 24 hoursOpen Monday to Friday.Contact us if you have any questions regarding our ... course, customer satisfaction is always our goal - so don't hesitate to contact us! export high quality 1/2" Glass and Tile Drill Bit