Explore Scientific 100° 20mm Waterproof Eyepiece Argon-Purged

Nitrogen-Purged and Waterproof: Internally sealed and purged with inert, dry nitrogen gas to prevent internal fogging, to halt the intrusion of fine particulates and fungus, and to maximize the life of the internal coatings. To make sure, each eyepiece is tested by submerging each unit in 1 meter of water for 30 minutes. Using advanced computer design, combinations of low dispersion and high refractive index optical glasses, and durable multilayer deposition coatings, Explore Scientific 100° Series™ hyper-wide field eyepieces are optimized to produce high contrast, high resolution, and superior flat field characteristics, and yes they are indeed ruggedized and waterproof to withstand the outdoor environment. Specifications Focal Length: 20mm Barrel Diameter: 2" AFOV: 100 degrees Eye Relief: 14.5mm Lens Elements: 9 Coatings: All lens-to-air surfaces are fully multi-coated Eyecups: Soft rubber folding style; Replaceable Weight: 38.1 oz