This magnetic mat box is a (C) element of the H&Y SWIFT system. The foldable lens hood is compatible with all (B) elements such as bridge adapter, plug-in filter holder and magnetic VND filter. It is used to prevent stray light or internal reflections from the lens. No vignetting up to 24 mm focal length with magnetic revoring adapter. No vignetting up to 22 mm focal length with screw-in adapter magnetic. Unlimited possibilities! The magnetic H&Y Revoring Swift System consists of numerous elements that allows versatile and creative combinations for photographers and filmmakers. The basic system is explained quite simply and consists essentially of only 3 components: Base (A) The base element sits directly on the lens. This can be a variable revoring, a classic adapter ring or a special adapter ring for wide angle lenses. Bridge (B) Next, one or more of the bridge elements is attached, such as the bridge adapter, a holder for plug-in filters or a variable ND filter. These elements can be combined with each other to use different filters together. Front (C) At the very front, the respective front element forms the end in the form of a filter holder, a lens hood or a matte box. Also these elements are all magnetic. Individual H&Y Drop-In, CPL, VND, ND and GND filters can be used on the bridge (B) and/or the front (C).