Leviton 6616-1XW fan speed control. Leviton controls are traditional rotary-style controls that are renowned for their compact, easy-to-install design and outstanding reliability. Trimatron controls are only half as deep as many conventional rotary-style speed controllers, providing an easy fit even in shallow wallboxes. They are furnished with wire leads to further speed installation. This Trimatron control is available in single-pole (one location), deluxe push-on/push-off version for fan speed control.