ARRI K2.0009434 (K20009434) Rota Pola Filter Frame 4x5,65 for LMB-5, LMB-15, LMB-25, LMB 4x5 and MB-19. The ARRI Rota Pola Filter Frame is compatible with LMB-5, LMB-15, LMB-25, LMB 4x5 and MB-19 matte box filter stages. It has the same width of a regular F4 filter frame and therefore only takes the space of one filter in a filter stage.

The glass inside is a round shaped circular polariser which takes less than 1.2 stops of light. The glass itself is available as a spare part (K4.0009410) and can easily be replaced by the end user when broken or scratched.
Note: It is not possible to use any other glass inside the Rota Pola Frame than the original supplied by ARRI.
The advantage of using a Rota Pola Filter Frame instead of a 4”x5.65” glass filter in a matte box filter frame is not caring anymore about having a rotating stage in your matte box because the glass inside the Rota Pola.