PROMASTER uses only the finest optical glass in the Infinity EL series. Coatings make all of the difference when you want a bright crisp image and PROMASTER has spared no expense here. These glasses feature PROMASTER's EXCLUSIVE TRANSBRIGHT? 99.3% light transmission coatings for the ultimate in bright, crisp images as well as PROMASTER's EXCLUSIVE REPELLAMAX? element repellent coatings that aid in keeping your optics free from dust and other environmental elements to ensure you get the maximum viewing enjoyment and capability from your binoculars. Every optical glass surface is fully broadband multicoated. This is not true of many far more expensive binoculars. The prisms are specially selected BAK-4 glass that has been both phase and silver coated to ensure true, sharp images. The ocular of every model has the maximum eye relief possible. This enhances the brightness and viewing ease. In addition to PROMASTER's superior optics and technologically advanced coatings, the Infinity EL series binoculars are waterproof, fog proof, and nitrogen filled to make sure that they always perform at an extreme level in extreme conditions. And if that is not enough...PROMASTER offers our No Fault Lifetime Warranty! Whether you run over them with a truck or drop them from an airplane, gather the pieces along with your original sales receipt and return everything to PROMASTER (along with a small processing fee) and we?ll replace your binoculars for you. Infinity EL binoculars are the pinnacle of optical quality and world class workmanship.