Materials and specs Chrome and formaldehyde free, vegetable tanned leather Sustainable twice tanned leather insole and outsole that will last Thick gauge leather, for body and strength Minimal to no stitching, for a natural & unstructured look and feel Slotted lasting points on footbed so the upper straps wrap around the foot, providing a glove-like feel .05 heel with twice tanned leather heel lift, Vibram inserts for traction Handmade and hand finished in Leon, Mexico Callista, the raw-edge, thick-gauge leather thong sandal for naturalists. Unlined for comfort, it boasts minimal stitching for a free-spirited look. The insole and outsole, both twice-tanned leather, offer flexibility, and durability, complemented by a Vibram insert for grip. The upper features three-way harness hardware and an adjustable sling-back strap with a buckle. With Callista, step out in style and experience barefoot comfort. Fit Guide: True To Size