I rememember it Kampervan;yes it looked just like a normal trannie except for the slot. I think it was called "Discatron" or something similar. One of my friends had one in the sixties. It only really worked if you put it down to play records. If you were carrying it the spring-loaded needle would jump at the slightest provocation, and gyroscopic effect would speed it up or slow it down as you turned left or right. I think they were only around for about a year.