105 mm dual hinged rings. Used on our 102 - 105 mm telescopes, these rings work with Stellarvue 105 mm OD tubes. They are not sized for other brands telescopes. The rings have five 1/4-20 threaded holes top and bottom. This includes a center hole, two holes that are 1.5” apart and two holes that are 60 mm apart. Made in the USA on our cnc machines using 6061 T6 aluminum.