Alegria Women's Opal SandalSize Chart Meet the Opal a stunning mix of clog and sandal! With a stain resistant leather upper, a padded sling back strap with a cute charm, and a slip resistant outsole, this twist on a classic is as stylish as it is practical. Featured in an Ink colorway on a leather upper. American Podiatric Medical Association (APMA) Accepted. Leather upper. Stain resistant upper. Leather and microsuede lining. Padded heel strap. Adjustable hook and loop ankle