A part of the modular Astro T-2 system, the Alpine Astronomical Baader 2" to 1.25" Reducer Adapter allows you to use smaller eyepieces in larger holders on focuser drawtubes, visual backs, Barlow lenses, diagonals, and other accessories. The adapter has standard 2" eyepiece filter threads, plus male T-2 camera threads for easy attachment of T-rings or T-2 adapter rings for the eyepiece. A separate T-2 ring protects this thread when it's not in use.