AstroStreet GSO 0.5X Focal Reducer, 2" (50.8mm) Diameter, Made In Taiwan

The lenses are also made of 3-bead apocromatic lenses, and the coating is made of very good quality Hooley multi-coat The large lens with an effective diameter of 0.9 inch (23 mm) is very high performance and does not vignetrate even with long focus eyepieces [Magnification] 2.5x [Lens] Apocromat 3 Element Airspaced [Sleeve Diameter] 1.25 inch (31.7 mm)