Finder purchased from Black Forest Observatory as a finder scope for a big telescope. It has a 3-inch aperture and is mounted in PVC with a PVC connector on the back which will hold an eyepiece. It may have to be extended to reach focus since I have not tried it for a long time and am not sure.
I am fairly sure that the focal length is around 13 inches. It is not a good lens and does not make a good telescope but at low powwer it may work as a big finder. I have never used it for a finder.
I will take $30 for it postpaid in the continental USA.