Plug connection 2 "on T-2 / M48 (T-2 component # 16)
 
Telescope side with 2 "outer plug diameter and 48mm filter thread for 2" color u. Fog filter
On the eyepiece side with T-2 and M48 external thread (under the removable M48 stop ring)
Effective overall optical length only 2.5mm
Safety groove on the 2 "outer diameter - so that even the heaviest accessories cannot fall to the ground!