The Teleskop Service Optics Adapter from M69x1 to M48x0.75 is for TS 2.5-inch Flattener and TSLPR3 Monorail Focuser.
TS-Optics M48x0.75 adapter for the TSFLAT2.5 full size corrector:
This adapter allows attaching accessories like camera adapters, off-axis guiders, using their 2-inch filter thread of M48x0.75.
It has been made deliberately with a relatively long optical path of 36.5 mm. As the TSFlat2.5 has a long working distance of 87 to 106 mm, this adapter allows bridging this distance without unnecessary spacer rings.
The provided 2-inch filter thread at the inner side allows you to attach a 2-inch nebula filter without changing the distance from the flattener to the camera.The M48x0.75 connection for the female M69x1 thread of the TSLPR3 3-inch monorail focuser:
This focuser is used with the RC telescopes from TS-Optics, Astro Tech, GSOs of at least 10-inch aperture. The adapter fits directly to the female M69x1 thread of these focusers.
Of course, the female M48x0.75 thread of the adapter can be for accepting 2-inch filters, but also for the adaptation of the 2-inch corrector TSRCFlat2 for RC telescopes.
Then the corrector is sunken into the focuser. The mechanical distance from the male M48x0.75 thread at the camera side to the female thread is 10.5 mm (the male thread is not taken into account). So if you screw the corrector directly into the filter thread, then you have a working distance of 98.5 mm from the M48 thread connector of the adapter.