Listing is for 1 (One) Service Caster 4" x 1-1/2" (4" x 2" pictured) Polyurethane on Cast Iron Keyed Drive Wheel.
Bore Diameter: 1/2"
Hub Length: 1-5/8"
Tread Durometer: 90-95 Shore (A)
Wheel comes standard with 2 set screws. One on the keyway and one 90 degrees from it.