Urth 77mm ND64-1000 (6-10 Stop) Variable Circular Lens Filter with 20 Layers of Nano-Coating Plus+Urth 77mm ND64 1000 (6 10 Stop) Variable ND Lens Filter Plus+ provides 6 to 10 f stops of light reduction, giving you greater creative control in bright changing light. By blocking 6 to 10 f stops, you can use wider apertures in bright variable light for shallower depth of field effects, and slower shutter speeds for long exposure effects without overexposing your images. Urth 77mm ND64 1000 (6 10 Stop) Variable ND Lens Filter Plus+ range features 20