These are 2-1/2" Diamond Lite Wheels from Dubro.
FEATURES: Black impact absorbing foam construction pre-mounted.
Gray plastic eight spoke rims.
Eight Rib tread design.
INCLUDES: Two 2-1/2" Diamond 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")