insole: narrow fit, leather, no appliqués, solid color, buckle fastening, round toeline, leather lining, rubber sole, flat, contains non-textile parts of animal origin, mules.BIRKENSTOCK Mules & Clogs. insole: narrow fit, leather, no appliqués, solid color, buckle fastening, round toeline, leather lining, rubber sole, flat, contains non-textile parts of animal origin, mules. Soft Leather