The Sky-Watcher 2" Erecting Prism is angled at 45° and will provide a fully corrected image when used with Refractor or Maksutov-Cassegrain telescopes with 2" focuser connection, making it especially useful for daytime terrestrial observations. Can be used with either 1.25" or 2" eyepieces. Eyepiece compression ring with both 1.25" and 2" adaptors. Threaded for 2" filters. Patented 2” diagonal interface designed for anti-deflection and anti-slip function. Features broadband anti-reflection coatings and phase-coated roof prism for excellent light transmission and contrast.