Baader Planetarium T-2/ T-2 Inverter Baader"s growing line of threaded couplers enable enthusiasts to convert T-2 threaded parts for alternative thread sizes or genders. These convertors allow users to firmly couple to various manufacturer"s telescope focuser threads or to combine T-2 parts into useful configurations. The fully sharp V-threaded and blackened internal surfaces cancel any stray light reflections and the precision threading guarantees a proper fit.