50X18mm Black Luggage Suitcase / Inline Outdoor Skate Replacement Wheels with ABEC 608zz Bearings Brand New Luggage / Inline Skate Replacement Wheels Size:50X18mm Standard Center Bearing ID is 6mm (.236") Each wheel size is sold as a SET of (2) Wheels. You're bidding on one set of (2) wheels ONLY Please see the attached image for the approx. wheel widths for each diameter.