very old 3.5" f/10. bakelite tube. nice adjustable cell. looks like skyscope from 50s but not sure. mount is definatly criterion from their old 4" f/12, not sure how these got put together. hardwood tripod. focuser is .965 with 20mm HM. which slides for focus. images are very good, the mirror is excellent. great for collector and only 60.00 plus shipping.