Polarizer: Designed for dimming an excessively illuminated target environment. Offers 19 settings for dimming. Prevents reticle "Washout." Enhances reticle visibility in challenging lighting conditions. Facilitates quicker target acquisition. Flash Guard: Intended to prevent lens flares during daytime use. Can be screwed directly into the M22 scope or used in addition to the polarizer. Conceals objective lens reflection. Reduces lens glare. Provides protection against scratches and damage to the lens. Feel free to ask if you need any further clarification! Mfg: Meprolight