Single and Twin Lever, with trim switch Attractive and astonishingly simple in design, the SL-3 is the most versatile family of controls. These throttles accept nearly every type of cable, including 33- type universal and Merc/OMC oem-type, which makes installation a lot easier and less time-consuming. Some features include, trim switch in handle, push button warm up and neutral interlock, which prevents starting in gear.