Summary

I'm a little obsessive about not losing things like lens caps, but my usual strategy is to just hold it my hand. No more!

ID on ring is 38mm.

Instructions

This thingy is printed in two parts, and glues together around the narrow portion of the neck strap. You could combine the two pieces, but regardless of how you orient it, you'd probably need support. I think the two piece strategy is solid. Do a nicer job of gluing than I.

I tried to polish the face that says LEICA using 1500 grit paper, but there are a couple irritating bubbles in my Kapton, and it now it just looks a little rough.

But it works perfectly!

Leica D-Lux 4 Lens Cap Holder Thingy