Spitfire Bighead Wheels from Spitfire are 54mm/99a. Sold in sets of 4. Designed to dominate the streets. Features - Height: 54mm - Durometer: 99a - - Designed to dominate the streets. - - Hand poured and 100% made in the USA - Guaranteed against any and all defects - Exclusive die process for all colored urethane allowing the special formula to maintain its performance - - Sold in sets of 4 - Bearings and spacers not included.