With more than 250 years of footwear heritage behind every design decision, Birkenstock introduces the Callan as its newest entry in the casual closed-toe slip-on category — a versatile, everyday shoe that blends the brand's signature orthopedic comfort with an effortlessly wearable silhouette. The upper is crafted from soft suede leather, a split leather with a velvety napped finish prized for its flexibility, breathability, and high moisture absorption capacity, while elastic inserts at the entry allow for easy on and off without sacrificing a snug, secure fit. A collapsible heel adds further versatility, allowing the Callan to be worn as either a fully enclosed shoe or a relaxed backless slip-on depending on the wearer's preference. Underfoot, the anatomically shaped Birkenstock Shoes S.