The Explorer is a classic aviator-style frame with adjustable features and multiple sizes to ensure an excellent fit. The frame is constructed from corrosion-resistant monel, a metal alloy that won't react with your skin. Integrated spring hinges ensure long-term comfort and durability. The matte finish, available in black or silver, has a luxurious texture that compliments the appearance of the EnChroma lenses. A leather-covered aluminum case is included with a magnetic closure and a slim design that fits easily in pockets. The size medium measurements are 55-16-135 and the large is 58-16-140 (mm). The size large Explorer in matte silver is our most popular style.