Slim Adjustable ND Filter Feature:
-- Reduces the amount of light reaching the film without affecting the color.
--Applies slow shutter speed under strong sunlight exposure.
--Glass mounted with high pressure press technology.
-- Made of high quality optical glass by K&F Concept technology.
--Wider outer optic to help reduce vignetting at wide angles.
--Extinction paint seiko manufacturing,To achieve the testing sights on military standard.