Feilong Drilling Spare Parts Company was established in 1983. Our company can supply drill bits and PDC bits which used on the oilfield and water well, the sizes: 5 7/8"--17 1/2"(both insert drill bits and steel tooth bit), if you need, please do not hesitate to contact with me. Website: http://www.xydrilling.com Mail: yongli19830517@hotmail.com (also my MSN) Skype ID: lilylily9571