Birkenstock Women's Arizona Slide Sandals,Purple,40 M EU / 9-9.5 B(M) US Leather / Suede eva sole Birko-Flor - Made of acrylic and polyamide felt fibers, this material is a soft fabric with a smooth leather-like finish. The original Birkenstock footbed - Featuring pronounced arch support, deep heel cup, and roomy toe box. Footbed molds and shapes to your foot. EVA - Flexible, lightweight, durable and shock absorbing.