Thin, flat, steel belts ranging from 0.008 to 0.035 in (0.02 to 0.09 cm) in thickness and from 7/8 to 8 in (2.2 to 20.3 cm) in width have been successfully used. The pulleys should be faced with a thin layer of cork. Steel belts can be run at speeds as high as 10,000 ft/min (3.0 km/min). It has been claimed that a 4-in (10.2-cm) steel belt will transmit as much power as a 19-in (48.3-cm) leather belt.