... Size: 6",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 ... ",12 1/4",14 3/4",17 1/2", etc. IADC Code:4-- Series, 5-- Series, 6-- Series,etc. Air Cooling ... Air cooling roller bearing package. Balls lock the conewhich reduces the probability of cone-dropping to minimum.Main Type AvailableSize: 8 1/2 ... ",6",6 1/2",7 1/2",8 1/2",9 1/2",9 5/8",9 7/8",12 1/4",15",15 1/2",17 1/2", etc. ...