The JMI Telescopes Large Format SCT Visual Back Adapter for NGF-XTc allows large 10-14" catadioptric telescopes to accept the JMI Telescopes NGF-XTc focuser.
The front (where light enters) has 3.25" SCT-style female threads, and the rear has a 4" threading matched to JMI's NGF-XTc focuser.
Made in the USA.