This 10-inch RV brake hub assembly by Lippert is designed for 4, 400-lb. trailer axles, has a 6 on 5.5" bolt pattern and is made from durable, solid iron. Specifications•Compatibility: Lippert 3500 Pound Idler Axles•Brake System: Electric•Capacity (LB):3500 To 4400 Pound•Diameter (IN):10 Inch•Bolt Pattern: 6 X 5-1/2 Inch•With Bearing: Yes•With Oil Seal: Yes•With Mounting Hardware: Yes 3500 To 4400 Pound Capacity Electric Brakes With Bearing Cones. Seal. & Grease Installed | Lippert Brake Drum Hub with Bearing Kit, 10"