SESTO SENSO is designed to be connected to the shaft that you can see in your focuser by removing the coarse and fine knobs. Most of the focusers in the market have a shaft with 25mm diameter and SESTO SENSO will connect to this shaft out of the box, without the need for adapters. Other focusers may come with 26, 33 or 37mm diameter shafts: in this case you will have to add also the optional 26, 33 or 37mm adapter for SESTO SENSO. Any other diameter won’t work. SESTO SENSO is designed to be connected to your focuser without the need of external and uncomfortable brackets.