Designed specifically for the Sky-Watcher Esprit-150 ED Apo Refractor, the new three-lens Focal Reducer/Flattener has a reduction factor of 0.77x. It comes with a standard adaptor with M48 thread edge and 55mm back focus for use with Sky-Watcher's M48 Canon EOS (code 20237) and Nikon (code 20238) adaptor rings. After removing the adaptor, an M71x1 internal thread with maximum 75mm back focus is available for self-made adaptor solutions. The Reducer/Flattener produces a fully illuminated and corrected image circle of 34mm diameter and is therefore perfectly suitable for image formats up to APS-C but can also be used for full format.