Birkenstock Mayari - Birko-Flor™ & Birkibuc™ black 1 Women’s size 40 (9-9.5) In good preowned condition see wear on right bottom heel, plenty of life left Black Premium leather or Birko-flor™ upper with adjustable buckle closures to ensure easy on-and-off wear and a secure fit. Birki-flor is made of acrylic and polyamide felt fibers Birkenstock's suede contoured footbed offers firm stable support, a neutral stance with room for toes to stretch and spread, and a natural walking motion that encourages optimal toe movement and blood flow.