These are the Ground Assault S Compound Tires for the HPI Firestorm, HPIC0510. FEATURES: Made of Rubber Black in Color Square Knobs INCLUDES: (2) Tires (2) Foam inserts REQUIRES: Wheels SPECS: Outside Diameter: 3.93" (100mm) Inside Diameter: 2.2" (53mm) Width: 2.36" (60mm) HPIPart HPI4411