Here's a few pics of what these look like.
The below 67-8 & 69 tape pics are OPENED pictures.The ones for sale are still sealed in cellophane like the 1970 below is,but I wanted to show others what they look like & came with inside.These were the very first years that Chevrolet released a Demo tape for their 8tk units.They would put these in the console/glovebox upon delivery.Be it underdash or incorporated into the radio.
It was possible and has been documented for a 1969 car to find a 1968 Demo tape in it,or a 1970 to find a 1969 Demo in it,as there was some overlap between the new model years.
.........................1967-8.....................1969........................ 1970
These are the optional 8tk cartridge holders that fastened to the bottom of the doors on ALL vehicles with existing bottom trim screws.The dense dark foam inside kept the tapes snug against the panels.
.................................................. .1969 Demo tape
.................................................1 967-8 Demo tape