I got this retro kit on Ebay in a torn and crushed box for a good price. Part of the Tricorder was glued together and a couple of parts were missing, but the major assemblies were basically all there. Surprisingly, the kit still had the instruction sheet in the box.  My memory of the model was pretty hazy as I was 3 or 4 years old when these were out, but when I really looked at the parts I was amazed at how different they were in comparison to the "Original Series" TV props.