features:<br />-100%  and high quality.<br />-this diamond coated core drill bit removes a complete circleglass， tiles， marble， granite， ceramic or other.<br />- materials and only needs water for lubrication.<br />- always use lubrication water， otherwise the diamond core drill will burn.<br />- works better with a electric drill   <br />- start your hole diagonally， make a round trace and then hold drill straight.<br /><br />specifications:<br />model: 20 pcs 3-40mm<br />quantity: 20 pcs<br />size:  <br />3-40mm:<br />3/4/5/6/8/10/12/14/16/18/20/22/25/26/28/30/32/35/38/40mm <br />0.12/0.16/0.20/0.24/0.31/0.39/0.47/0.55/0.63/0.71/0.78/0.87/0.98/1.02/1.10/1.18/1.26/1.38/1.50/1.57 inch<br /><br />4-40mm:<br />4/5/6/7/8/10/12/13/14/15/16/18/20/22/25/27/30/32/35/40mm<br /><br />3-50mm:<br /> 3/4/5/6/8/10/12/14/16/18/20/22/25/26/28/30/32/35/38/50mm <br />0.12/0.16/0.20/0.24/0.31/0.39/0.47/0.55/0.63/0.71/0.78/0.87/0.98/1.02/1.10/1.18/1.26/1.38/1.50/1.97 inch<br /><br />6-50mm: <br />6/8/10/12/14/16/18/20/22/25/26/28/30/32/35/38/40/42/45/50mm <br />0.24/0.31/0.39/0.47/0.55/0.63/0.71/0.78/0.87/0.98/1.02/1.10/1.18/1.26/1.38/1.50/1.57/1.65/1.77/1.97 inch<br /><br />packaged included:<br />1 x 20pcs diamond coated hole saw drill bits