This nice size positive meniscus lens is 139mm in diameter by approximately 229mm focal length. It has an edge thickness of 2mm and a center thickness of 12mm. It has a nice pinkish/purple anti-reflective coating. These might have light cleaning scratches or some coating breakup that won't interfere with its use. Actually this is one of the elements from our L13001 triplet that sold out. Mounting is 172mm diameter by 55mm deep. Only have a few.