I'd like to sell some miscellaneous not-useful-to-me items I found lurking on a shelf, and this is one of them.
The Canon Auto-Up is a clever attachment that slips over the front of the camera lens and is held on by a mounting screw that presses on an internal ring. The bottom part is a glass close-up lens and the top part is a rectangular plastic lens that "fools" the rangefinder into proper focusing with the close-up lens. This one is marked "For Canon Lens 50mm f/1.8 40" ~ 22" or 100cm - 56cm" and comes in a slightly worn but intact felt-lined fitted case. It also has a small arrow that's visible when focusing that I believe is a parallax correction showing the top of the image field. The glass is clear and clean but has some very faint cleaning marks.
$20 shipped in the US. PayPal is OK.