Waterproof - Fog Proof - Phase -corrected - Fully multi-coated - Multi-position tapered eyecups - Rubber armored - Tripod adaptable - Tethered objective lens covers - Center diopter............. Go to www.elknut.com and then to the "Vortex Optics Page" for specific links to each of the Vortex Products. The links will provide in depth information on all the Vortex Optics!