Attracting visitors for over 145 years, the crystal cave in Kutztown, PA is a mainstay for adventure. Inspired by the unique geology and natural formations within the cave’s walls, this ProGrid Omni 9 offers a gemstone-like opulence. Iridescent in color, the shoe has been treated with an anodizing process that creates a “crystal” effect throughout the upper. An open mesh base shifts between colors when the light changes focus.