These collapsible finders are wonderful things to use, though - they fold flat (making it easier to fit your Leica into a bag and keeping it out of the way when it's on your shoulder), give you a perfect 1:1 view of the world (meaning you can keep both eyes open and effectively super-impose the frameline onto your normal vision), and have a small but easily accessible/adjustable lever that allows you to accurately adjust for parallax down to 3.5ft. 

I've included a couple of photos of it on my IIIg so you can see what it looks like in use and collapsed - needless to say, the camera and lens are not included with the viewfinder!

As you can see in the photos, this particular SYEOO has some "crackling" in the coating on the rear of the glass, but the glass itself is solid, the framelines are completely intact, and the view is totally unimpeded - you can't make out the "crackling" at all when looking through the viewfinder itself. There's no damage to the chrome anywhere on the viewfinder, and everything moves smoothly and easily. I don't think I've ever seen a SYEOO in such good condition before - most of them look absolutely battered by this point.

All in all, this is a lovely thing that makes shooting 135mm lenses on any Leica or LTM-compatible camera an absolute joy. Even if you have a later M-mount camera, it's a vast improvement over the tiny 135mm frameline corner "nubs" in a 0.72x finder! 

This will be thoroughly and carefully wrapped in bubble wrap and packed in a box before shipping to keep it as safe as is humanly possible.