If you want to use your telescope visually with ESATTO 3" or if you want to connect a camera with a 2" nosepiece, just connect the 2" visual back for ESATTO 3" to the M81 thread of the focuser draw tube. This adapter has an internal brass compression ring to avoid scratching the inserted nosepiece as well as 3 locking screws (120° separation) for a perfect fit, even for heavy cameras or accessories.