Extension ring T-2 female / M48 male (converts M48 female. in T-2
female).
The adapter can be inserted into the 2″ filter thread of 2″ adapters or eyepieces
be screwed in and reduces the thread to T2. With that can
make the adaptation to a T2 external thread.
T2 internal thread (M42x0.75)
M48 x 0.75 male thread (2″ filter thread)
Overall length only 3.5mm