Pair of light duty end bearing flanges with a 3-3/8 inch shaft offset. These mount at the ends of the torsion shaft and bolt to the wall to keep the bar level and supported. If the shaft's wobbling or the bearings are shot, the door will track rough and the cables can slip. The 12-gauge steel is rated for standard residential setups. The 3-3/8 inch offset is a common dimension on most home garage doors, but measure yours before ordering since offsets vary. Two flanges in the set, one for each end of the shaft.