Sram RED Rear Derailleurs Premium Ball Bearings Kit Inner Diameter - 2 inch (2") it provides protection against dust

it provides protection against dust and contaminants

30mm x 62mm x 23

Size: 20mm x 47mm x 31mm

Dimensions (Inches) a e b s1 s2 g w Bi n 1-7/16" 5-1/2" 4-1/8" 1-1/2" 1/2" 3/4" 19/32" 2-25/32" 1-11/32" 9/16"

Sram RED Rear Derailleurs Premium Ball Bearings Kit Inner Diameter - 2 inch (2") it provides protection against dustBall Bearings for Sram RED Rear Derailleurs Closures: Rubber Sealed Closure Side: Double Sided Seals Lubrication: Low Friction Grease Material: Corrosion Resistant Chrome Steel Balls: High Chromium Steel 52100 SAE Steel Balls Cage: Low Friction Steel Precision: ABEC 1 Quality Brand: VXB Quantity: Set of two Bearings Location : Rear Hub