Here's an image every GRiD collector should copy. A GRiD Compass used on
STS 51-G with a picture of Spock on the screen:
http://images.jsc.nasa.gov/images/pao/STS51G/10062178.jpg
Put this picture in your ebay ad, and watch the price skyrocket! (BTW,
I've never seen an original Compass offered on ebay, but one sold for $700
in a "normal" auction a couple of years ago.)
-- Doug