GPObright is a proprietary coating process that maximizes light transmission through each surface of an optical element. As light hits an optical surface, normal uncoated high-performance glass can reflect up to 5% of that light, redirecting this light so it does not transmit through the optical system. However, when these high-performance lenses are vacuum-coated with GPObright lens coatings, up to 99.7% of the available light passes through each optical surface. Furthermore, when every surface of the entire optical system is properly coated, total light transmission can reach up to more than 92%, making the optical image of a GPO binocular or riflescope even in the lowest light conditions.