This is the PrimaLuceLab 37 mm Adapter for Sesto Senso 2!
This 37 mm adapter allows you to install your SESTO SENSO 2 onto focusers which have a 37 mm diameter shaft, like the 3.5-inch FeatherTouch, FSQ-130, or other focusers with 37 mm diameter large shaft.
Your SESTO SENSO 2 already connects to focusers which have 25 mm diameter shafts (this includes most of the focusers on the market), but in order to connect it to focusers that have the larger 37 mm diameter shaft, you will need to add this adapter.
This 37 mm adapter is installed on the focuser instead of the double 10:1 knobs (macrometric and micrometric), then you can install SESTO SENSO 2. Included with this adapter, is the longer bushing which is used to connect SESTO SENSO 2 to the focuser. You will also find installation instructions (in English and Italian).