****************************** Please read the profile before purchasing. ****************************** This is a Bahtinov mask for attaching to a camera lens with a 67mm filter diameter. It's made in the shape of a lens cap, so it's easy to attach and remove. It makes focusing easier when taking astrophotographs with a camera lens. The slits are made with many openings to increase the amount of light. The fourth photo is a reference photo. Focus is confirmed with Ras Algethi, a 2nd 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 such things. Camera lenses and other equipment are not included in the sale.