Want to Buy WTB 40mm filters for Canon LTM lenses

I'd like to get some filters for use on Canon LTM lenses for my Canon-P. These take a 40mm filter, not the much-more-common 40.5mm. Send me a PM if you've got any kicking around in the box of stuff you haven't used for years.

Alternatively, I could use a 40mm-to-anything step-up ring, but these don't seem to exist

Wasn't there a song that went "turn that frown upside down"?

Ebay items 121560045141 (UK) and 361409045245

Thank you!!!! This is perfect, I already have 40.5 to 52 step-ups for some of my LF stuff.

If you want elegant have SK Grimes make you a 40mm to 39mm ring. They will add a groove so that Leica lens hoods will clip on properly. I have one for my 50mm f/1.8 Canon lens and I use a vented Leica 12585 lens hood.