The Tiffen Multi Rota Tray Variable Neutral Density Kit is a single geared rotating tray for matte box use that simulates a variable ND by included a rotating 138mm linear polarizing filter, and a fixed 4 × 5.65-inch circular polarizer filters.
Can also be used just as a rotating polarizing filter by removing the extra polarizer. Geared and can be remote-controlled through a FIZ system.