When designing the Prime Binoculars, Bushnell started out with fully multi coated optics to increase light for a brilliantly bright picture. Then they used BAK4 prisms to increase brightness even further. To guarantee the weather elements don't get in the way, Bushnell gave these Prime 10x42 binoculars our exclusive EXO Barrier lens coating to shake off water, dust, and debris. Next, they made them IPX7 fully waterproof to inspire confidence in the field. Finally, Bushnell gave them a full, transferable, lifetime Ironclad Warranty so you can buy with confidence. Exclusive EXO Barrier Protection - Bushnell’s newest and best protective lens coating molecularly bonds to the glass, repelling water, oil, dust, debris and preventing scratches. IPX7 Waterproof construction - O-ring sealed optics stay dry inside, when immersed in three feet of water for up to 30 minutes. Multi Coated Optics - Multiple layers of coatings on all lens surfaces increase light transmission and image brightness. Full lifetime Ironclad Warranty