... ",6 1/2",7 1/2",8 1/2",9 1/2",9 5/8",9 7/8",12 1/4",17 1/2", etc. IADC Code:4-- Series, 5-- Series, 6-- Series,etc ... ",6",6 1/2",7 1/2",7 7/8",8 1/2",9 1/2",9 5/8",9 7/8",12 1/4",14 3/4",17 1/2", etc ... . IADC Code:4-- Series ... , 5-- Series, 6-- Series,etc ...