Gosky SCT to 2" Eyepiece dapter for All Schmidt-cassegrains - Use 2" Eyepieces/Lens on SCT telescope - For Celestron Sky-watcher and other Scts SCT to 2" Eyepiece dapter for All Schmidt-cassegrains telescope Female threads on to the rear cell of Schmidt-Cassegrain telescopes. Brass Ring inside the tube- protect the eyepiece from scraching. All metal construction and anodizing aluminium process, durable for long time use.