This is a Zeiss student microscope head modified for astro use. An integrated (easily removable) RKE barlow element allows focus in Newtonians with 2" focusers, and yields around 2X. It might also be used in some 1.25" setups that have adequate in-focus. Accepts 1.25" EP's.
This one is great for lunar and planetary observing, but seems a little dim for deep sky. It might be because of the 21mm aperture, but I'm not certain.
It's in excellent condition, with just a few external paint & barrel scrapes from normal use.
$245 shipped USPS Priority to the lower 48. Paypal preferred.