VIPER HD 10 x42 ROOF PRISM BINOCULAR The Viper HD-a premium-quality binocular packed with everything you need and nothing you don't. Rugged, compact and lightweight (one of the lightest full-size binoculars to date), it's easy to see why the Vipers are award winners. Add in HD (High Density) e xtra-low dispersion glass for impressive resolution and color fidelity and the Vipers change more than the game. They change the results, too.