These Arri MB-20 Filter Rings are used between the R2-R3 adapter ring and your lenses or a reducing ring.
These Filter Rings allows the user to step down to a smaller lens diameter by reducing the (4 1/2")114mm diameter of the R2-R3 adapter ring. The Filter Rings also have an enclosed area where 114mm filters can be inserted and secured. A screw on coupling keeps the filter inside the Filter Ring. These filter rings will step down to 114mm, 95mm, and 87mm.
CAT 333064 K2.49109.0, 338666 K2.49102.0, 711312 K2.52205.0