Brighter images - Fully Multicoated optics effectively reduces reflected light and increases the transmission of light giving you a brighter image. Waterproof - Regardless of how heavy the rain is coming down or an accidental drop in the water, this sealed and gas-purged optic will remain waterproof. Fog Proof - Paired with a completely sealed chassis, nitrogen gas is used to purge air from the optic to help maintain internal fog-proof and waterproof capabilities. SFP – Second focal plane allows the reticle to stay the same size whether zoomed in or out.