Lowepro Fastpack BP 250 AW III Black Canon GoLive that includes a lens construction that includes a lens construction that consists of special glass materials including LD (Low Dispersion) and GM (Glass Molded Aspherical) lens elements which is used to effectively eliminate aberrations from taking place Providing a magnification factor of 0 The Lowepro Fastpack BP 250 AW III Black is designed for the user to access the compartment by swinging the backpack to the left side and accessing gear from the side zipper The Lowepro Fastpack BP 250 AW III Black offers a dedicated zipper compartment for a 13" laptop directly behind the shoulders for security