FOX MAIN CORE SPARK Adult MX GoggleOunce for ounce, our Main Core Mirrored Lens Goggles are the best value on the market and feature the Variable Lens System (VLS). VLS makes your goggles compatible with both standard lenses (stock) and injection molded lenses (sold separately) within the same frame. With an expansive viewport, triple layer foam, and tear off functionality, they're a heavy hitter on the dirt while being light on the wallet. All new design offers best in class viewport