SV220 H-Alpha 3nm and O-III 3nm Ultra Dual-Narrowband Filter enhances astrophotography by reducing stray light and light pollution, enhancing image clarity, suitable for capturing deep-sky objects. Full-frame design ensures no vignetting, broad field of view, and accurate color reproduction. It improves image uniformity, clarity, and contrast, ideal for high-res deep-sky observations, maintaining consistent quality across the frame. SV226 filter drawer adopts integrated CNC molding and anti-light leaking design. It can compatible with 1.25" & 2" specifications filters on the market. Strong magnetic attraction, prevent the filter from falling off. The threads on both sides of the SV226 filter drawer are M48x0.75 internal threads and M42x0.75 external threads, which are compatible with most specifications of astronomical cameras. Note: If you want to connect with a dslr camera, you need to use an additional camera adapter.