JT paintball makes a variety of replacement thermal lenses to replace your current JT lens. The most common JT lenses are the Spectra lenses which fit the Proflex, Flex 8 and Flex 7 mask amongst others. There is also the JT Elte lens which has a narrower field of view and can be found on the more bufget range of JT masks. Most of the JT Lenses are Thermal, which means they have a dual paned lens, similar to a double glazed window, which prevents fogging. Single, anti-fog lenses are also available, but mostly just for the Elite goggle.