DuraSoft rollers have a smooth surface and are permanently bonded to a steel insert. Designed to be mounted on a shaft. A hub extends past the roller and is supplied with two set screws (90 degrees apart) to fasten onto the shaft. The "teardrop" holes allow the roller to flex for firm yet non-damaging contact. Rollers are available in urethane material with hardness ranging from 35 to 95 durometer.