Here's a cool waist level finder made by Kuhn Wetzlar to mount in the accessory shoe on your rangefinder or SLR with a 50mm lens.
It is a great accessory, particularly for landscape photography. It lets you step back and look at the image, leading to a more contemplative and thoughtful style of photography.
This one shows moderate cosmetic wear but works perfectly. There is a small amount of rusting on the hinge of the magnifier and the lens has a few fine marks on the front element but neither impacts the function of the finder.