******************************* Please read the profile before purchasing. ******************************* This is a Bahtinov mask for attaching to a camera lens with a filter diameter of 82mm. It's made in the shape of a lens cap, so it's easy to attach and detach. It makes focusing easier when taking astrophotographs with a camera lens. The slits are made with many openings to gather more light. The fourth photo is a reference photo. Focus is confirmed with Antares, a first-magnitude star. The structure may be changed due to use. This is a handmade product, so it is listed as "no noticeable scratches or stains." Please refrain from purchasing if you are sensitive to imperfections. Camera lenses and other equipment are not included in the sale.