Leica Leitz Telyt 560mm F6.8 R Lens with Extension Tube
This is a funky modular lens that slides to focus. For normal operation, attach the front to the longer tube and for extra reach you can add the smaller middle portion.
The front element has a small scuff near the middle. There is also a moderate amount of crud behind the front element. With a lens this long there should be no effect on image quality. Otherwise the lens is in excellent condition with light wear. Caps are included.