Bushnell H2O 8x 25mm Waterproof Binocular Compact & Durable Waterproof Design Is O-Ring Sealed & Nitrogen-Purged For 100% Reliable, Fog-Free Performance Large Center Focus Knob For Easy, Precise Adjustments Compact roof prism binoculars with 8x magnification and 25-millimeter objective lenses BaK-4 prisms and multi-coated optics offer crisp clear images with improved light transmission 100 percent water and fog proof construction: O-ring sealed and nitrogen purged Non-slip rubber armor absorbs shock and offers a firm grip; twist-up eyecups Large center focus knob; long eye relief; limited lifetime warranty