Petroff Matte Box is a fully modular, no tool assembly system where you can add or remove stages or adjust system components without the need for tools. The Petroff Matte Box Kit includes 4x4 matte box (P44-2W), two filter stages, side flags, 15mm support adapter (SS-10-15), top flag & your choice of one lens ring. All filter stages rotate 360 degrees independently, but in order to operate comfortable with polarizing filters one or two stages could be blocked from rotation. The snap on system allows the user to easily remove or add filter stages. The 4x4W size works with external lens diameters up to 110mm.