The Vanguard 8x42 SDT series binocular features fully multi-coated lenses and BaK4 prisms, ensuring exceptional light transmission even during low light situations. SDT binoculars are nitrogen-charged and O-ring sealed, making them 100% fog proof and waterproof. The strong aluminum die-cast body and tough rubber armor provide impact resistance during active use, while the large metal focus wheel allows for rapid focusing. Eyeglass wearers will appreciate the long eye relief and deluxe twist-out eye cups. The ergonomic design of the SDT binoculars, their optical performance, 9.8’ near-focus distance and light weight guarantee a comfortable bird-watching or hunting experience.