Professional tool for commercial or occasional use -Taper Roller bearing hub -This listing is for a pair of hubs which is often fitted to camping trailers, jet ski trailers -4 stud with 4" PCD (PCD = Pitch Centre diameter - distance diagonally from one stud to another) -Fits a standard 1" trailer stub axle -Complete fitted with 3/8" wheel studs -The bearing races are already pressed into the hub meaning no specialist tools are required to fit the hubs. -The hub is also fitted with a grease nipple. SET INCLUDES THE FOLLOWING - 2 X Cast Hub (unplated) - 2 x outer bearing (complete with seal) - 2 x inner bearing - 2 x hub cap - 8 x wheel nuts.