These are 2" Super Lite Wheels from Dubro. Black impact absorbing foam construction pre-mounted. Gray plastic eight spoke rims. Seven rib tread design. Two 2" Super Lite Pre-mounted Wheels Wheel collars to hold them on the axle. May require reaming out the hole to mount on larger axle. Diameter: 50.8mm (2") Axle Diameter: 3.5mm (.141") Width: 17.4mm (.686") Weight: 5.22 grams each wheel pjm 2/10/02 ir/kh &