Very good performance three cone rotary bit, high downhole speed and long working life 9 7/8" ... ”),609.6mm(24”)660.4mm(26”)Available models: Steel tooth(IADC)111, 121,131117,124,126,127,136,137 216,217 ... , 227211,311TCI(IADC)415,435, 417,437515,525,535,545, 517,527,537 ... ,637,737512,522,532,612,622,632,7323 cone rotary bit 4 5/8"IADC537G