Cleaning out junk I came across a really old (25 years, I think) Oxford Illuminated Sight for a rifle or pistol. I haven't used it for 15 or 20 years so I don't know if it works, but it worked when it was put away.
This is an early red-dot type sight, of interest mostly to collectors, but it worked great. It mounts with a pair of scope rings. I have the instruction sheet for it. If you really want it, let me know by e-mail and I'll mail it on Monday.