3/4" hub bearing, usually intended for the backside of an extended right-front hub on an oval kart that utilizes the stepped size spindle.
Bearing is marked R12 RS
This bearing has an OD of 1...
1 Ton Bearing Races - Starlite "55" hubs provide the superior strength of permanent mold, high-density aircraft aluminum at weights comparable to the much higher priced magnesium hub assemblies...