The William Optics M80 to M48 Flattener adapter lets you use the Flat68III flattener with the Fluorostar 91, or the Flat7A flattener with the Fluorostar 120. This adapter takes the place of the original M48 rear adapter of each flattener and allows you to reach the correct backspacing required by either scope.
With this adapter, the Flat68III should be set to 5mm for the Fluorostar 91. With the Flat7A plus Fluorostar 120, the spacing should be set to 1.4mm.
|M80 x 0.75 female
|M48 x 0.75 male