Kurzweil PCX1 Polyphony Expansion Board (for PC2 Series)
PC2 Series power user? Need more polyphony? Then double your PC2/X/R's 64-note polyphony to 128 voices by adding the PCX-1 Polyphony Expansion Board. Requires Version 2.10 or better, with a version 2.00 or better boot loader.