A combination of the Schneider neutral density and 85 colour conversion filter.
Neutral Density Filter
Appears grey and reduces light reaching the film without affecting colour balance.
ND.3 - reduces light by 1 stop
ND.6 - reduces light by 2 stops
ND.9 - reduces light by 3 stops
85 Color Conversion Filter
Corrects colour temperature difference between the recording medium and the light source. Produces cooler results compared to the 85B which converts tungsten film to daylight.