... increases gauge holding capability. 3. Bearing Structure Air cooling roller bearing package. Balls lock the cone, which reduces the probability ... ….……….. ………………………………12 1/2 211, 121, 241, 537….14 3/4 131, 211, 537, 517….15 1/2 211, 121, 241, 537….17 1/2 131, 211 ... , 537, 517….18 1/2 211, 121, 241, 537….………..………………………………26 131, 211, 537, 517…. API Kingdream ...