Very good performance three cone rotary bit, high downhole speed and long working life 9 7 ... or valid L/C opened.FAQ(Frequently Asked Questions)1. How to place an inquiry or order? Answer: There are several ways ... from northern China to European about 30 days to Hamburg 35 days to UK and France, 38 days to Italy. To West of North ... 627,637,737512,522,532,612,622,632,7323 cone rotary bit 4 5/8"IADC537G