DuraSoft rollers have a smooth surface and are permanently bonded to a steel insert with the bearings held in place with snap rings. They come assembled with a socket head cap screw, spacer and locknut for fast easy mounting. The "teardrop" holes allow the roller to flex for firm yet nondamaging contact. Rollers are made from urethane material with hardness ranging from 35 to 95 durometer. Supplied with precision bearings.