The Variable Attenuator Ring Module (VARM) is a triple-wheel filter holder that contains three filters per wheel. The filters are made to our exacting specifications for transmission value and material quality. The VARM is adjustable in attenuation in 64 discrete steps of approximately 16% reduction each step from 400,000:1 down to 1:1. The VARM design allows it to be easily returned to exactly the same attenuation level as previously used.