…is more or less clone of Casio SK-1 that was manufactured for Radio Shack. Sometimes the current mind boggling prices of $60 or more for an SK-1s on eBay can be avoided by searching for the Concertmate – 500 instead. The seller of this auction however really felt compelled to post an excessive number of closeup photos of the keyboard and the box, maybe hoping that it would help to boost the value of this wanna be Casio SK-1.