\rHi BR101:
The VMS series is Impedance matching Volume Controls with a slider style switch. The SLS is the same except the front plate features a screwless design. There is an outer plate that covers up the screws holding the inner plate to the metal bracket. Many new houses are featuring light control switches that also hide the mounting screws. So now you have volume controls that match the step up lighting control plates as well.
TL/5256\r