The ProMaster Digital HGX Variable Neutral Density Filter variable neutral density filter providing light reduction of about 1.3 to 8.6 stops. The ND3 to ND400 density creates a darkening of the entire image, allowing you to photograph with a wider aperture or slower shutter speed than normally required. ProMaster Digital HGX filters are the most advanced optical filters available today for digital photography featuring: • Next Generation Digital Anti-Reflection Multi Coating – Specially formulated to minimize internal reflections created by CCD and CMOS sensors in a digital SLR. • REPELLAMAX™ Element Resistant Coating – This EXCLUSIVE ProMaster coating repels moisture, fingerprints, dust, dirt, and grime to ensure the sharpest images possible • Hardened Optical Glass – Ultra hardened optical glass resists surface scratching and stands up to the most intensive use. • Low Profile Anti-Reflective Frame – Ultra thin low profile frame helps prevent vignetting on super wide digital format lenses. The satin-like smooth finish helps to minimize reflected light. • Black Rimmed Glass – The outer rim of the filter glass is treated with a special black-ink.