These are 2-1/2" Super Lite Wheels from Dubro. FEATURES: Black impact-absorbing foam construction pre-mounted. Gray plastic eight spoke rims. Five Rib tread design. INCLUDES: Two 2-1/2" Super Lite Pre-mounted Wheels REQUIRES: Wheel collars to hold them on the axle. May require reaming out the hole to mount on larger axle. SPECS: Diameter: 63.5mm (2-1/2") O.D. Axle diameter: 4.4mm (.175") Overall width: 20mm (.788") Weight: 9.65 grams each pjm 02/10/02 ir/kh