Photos show the old Bower bearing on the left and the new Timken bearing on the right. more available. I was skeptical about buying this bearing as there is little information and the Timken website only lists it in a two bearing configuration. I was pleased to find that it was a snug fit for a Bower stock. I believe Timken bought Bower and kept his part number. Here are the important measurements as per my calipers: Inner bore (shaft) diameter: 30.25mm/1.19in. Width from front face to back edge: 27.87 mm./1.09 in. Cage OD (large tapered edge): 58.21 mm/ 2.29 in., Trailing edge OD (bearing protruding back): 44.52 mm/ 1.75 in.