The Casio SP-33 Privia Piano-Style 3-Pedal Unit for PX-150 and PX-350 features damper, soft, and sostenuto pedals all in a single unit that attaches to the CS-67 stand. The SP-33 supports half-pedal operation, so effects can be partially applied if a pedal is partially pressed.
Note:
The CS-67 stand is required in order to use the SP-33 pedal.