The brown version of the Tryom Electronic Chess (CC-700) is not at all rare. They are often found on Ebay. However the white version of this same chess computer is very difficult to find. Apart from the colour there is apparently no difference in the chess computers or the accessories which were issued with them. The serial numbers of my Tryom’s are 05383 (white) and 14473 (brown).
The chess program in the Tryom comes from the Compuchess stable, but does not seem to be exactly the same as the original Compuchess or the Compuchess Second Edition.