Introduced in 1992, the Sleep Machine and the Roller Woody took the ball bearing axle and gap adjustment system of the SB-2 and put them in a wooden body to create the first ball bearing wooden yo-yos. Originally offered in both varnished and painted maple finishes, the Butterfly-profiled Sleep Machine was later offered in laminates and various custom paint schemes. In 2014, Tom Kuhn also began producing Sleep Machine yo-yos with new Mandala-style Filigree and Solar Flare laser engravings.