This 4 x5.65" carbon fiber matte box is designed to clamp directly onto standard sized cinema lenses in order to be as lightweight and unobtrusive as possible.It includes multiple lens adapter rings to fit most standard front diameters sizes.Additional sized backings can be purchased separately.These adapter rings not only allow the matte box to directly attach to the lens, but it forgoes the need for lens donuts.Included in the package is one top French flag to provide flare protection.It also includes an 15mm rod attachment if you wish to mount the matte box via LWS rods.