The adapter fits to a male T2-thread and extends it to an M48x0.75 2" filter thread. With this, you can use connection adapters with female M48x0.75 thread.

Another application is the reduction of a 2" filter thread to T2. Screw the adapter into the female M48x0.75 thread and then a female T2 thread is at your disposal.

The adapter itself is only 2.5 mm short. As it disappears entirely in the M48x0.75 connection thread, the adapter has no effective optical path. At one side, the adpter has two slots which make loosening from the connection adapter easy.