Here's an obscure but amazing accessory finder for the original Canon F-1 and F-1n (but not the F-1N aka F-1 New). It's the Booster T Finder, which is an insanely sensitive meter for using the camera in negligible light. It overrides the camera's built-in meter and even includes a shutter timer that precisely measures off some crazy long shutter times. This is fully functional, in cosmetically gorgeous condition, and includes both of the ways to power it. Two of the battery which can be installed internally (one slightly used, the other still in package, always kept refrigerated over the years); and the external AA battery case with connecting cord that plugs onto the case, and then screws in in place of the internal battery. Also comes with the original leather felt-lined case.
I'd like to get $200 for this gem, but that includes shipping anywhere in the world.