The ARP 16-Voice Electric Piano was a 73-key electronic piano produced by ARP Instruments, Inc. from 1979 to 1981, with specially designed weighted maple action keys, similar to a grand piano.
There was also a headphone jack on the front panel and two inputs on the back for external inputs such as tape recorders etc.
The unit featured two brass pedals: right for sustain, left soft pedal or vibrato.
http://synthmuseum.com/arp/arppianobro.jpg