This adapter allows you to connect the ESATTO 3" focuser to the M117 thread of GSO/Orion/TPO Ritchey-Chretien 10", 12", 14" and 16" telescopes (both aluminium and carbon tubes).
By using the standard extensions that come with the telescope you can install the focuser at a precise distance from the OTA. Additional extenders may be required to reach focus with your camera, depending on the accessories you wish to connect.