6906DDU 30x47x9 Sealed Ball Bearing Skateboard Bearing the NJ306 inner diameter is

the NJ306 inner diameter is 30mm

the dimensions are 1/2" x 1 3/8" x 1/2"

and aerospace systems

UNF-2B h1 L3 L4 L5 d4 d5 S 5/8" 3/4" 0

3 mm Ball Bearing

6906DDU 30x47x9 Sealed Ball Bearing Skateboard Bearing the NJ306 inner diameter is6906DDU Sealed Ball Bearing 30mm x 47mm x 9mm 6906DDU Sealed Ball Bearing, 6906DDU bearing is made from Chrome Steel, 6906DDU bearing has Rubber Seals to protect the bearing from dust or any possible contamination, bearing is self lubricated bearings, 6906DDU bearing is already greased. 6906DDU Ball Bearing Ty[e: Deep Groove Ball Bearing Size: 30mm x 47mm x 9mm Inner Diameter: 30mm Outer Diameter: 47mm Width: 9mm Cage: Chrome Steel Lubrication: Grease