Baader Ultra Short SCT to T-Adaptor, 9mm optical length (BPSC2T2)
This adapter allows you to connect your T-2 thread (42mm) accessories to the larger SCT thread (2”). It has 2" SCT female threads on the one side and T-2 male threads on the other.
It has the shortest spacing length possible. It uses only 9mm of optical path length (8mm with the Delrin-ring removed).