The Baader # 1508020 inverter is a simple SCT externally threaded ring, which can be used to convert internal SCT threads to external SCT threads (gender changer). This adapter has a male SCT thread (2" x 24 TPI specification) all along its outside. Total adapter / SCT male thread length = 11.9mm (0.47").
It also has a short female M48 x 0.75 (2" filter thread) on one side, so it can also be used as an SCT male to M48 female adapter. Length of female M48 thread is approximately 2.5mm (0.1").
Baader part number: INVERT-2 or 1508020