This On/Off sustain pedal can be used on your digital piano as well  as a foot switch controller on synthesizer. It is  designed with rubber grip to the floor as well as on your foot to prevent slipping.

For those electronic keyboards with an input jack labeled "SUSTAIN," the FC5 is used in the same manner the sustain pedal on an acoustic piano is used. A specially designed rubber bottom grips the floor and stays put while you play. The FC5 can also be utilized as an FS controller for synthesizers, tone modules and drum machines.