Outer Diameter (OD): 100 mm (3.937 inches) Inner Diameter (Bore): 55 mm (or variations in inches depending on the exact sub-model) Width: 55.6 mm (2.189 inches) Locking Style: Features dual set screws on an extended inner ring for secure shaft mounting. Sealing: Equipped with high-performance standard seals (2F) to block out dust, grime, and oil.