Polyurethane Covered Bearing
From Free Knowledge Base- The DUCK Project: information for everyone
Urethane aka Polyurethane covered bearings (also known as molded bearings) feature a smooth urethane surface cast directly on precision-sealed ball bearings. They provide quiet, non-marring operation with excellent abrasion resistance and durability.
Used primarily in applications that require noise reduction, such as manufacturing or warehouse conveyor lines, Polyurethane covered bearings are just as the name says: bearings with a Polyurethane cover.
The polyurethane tire cover reduces the noise and vibration associated with bearing movement.