The Casio SK-1 is a small sampling keyboard made by Casio in 1985.It has 32 small sized piano keys, four-note polyphony, with a sampling bit depth of 8 bit PCM and a sample rate of 9.38 kHz, a built-in microphone and line level input for sampling, and an internal speaker. It also features a small number of four-note polyphonic preset analog and digital instrument voices, and a simple additive voice.All voices may be shaped by 13 preset envelopes, portamento and vibrato.