The Boston EVA is made from water-friendly material, giving you a flexible design built on the contoured footbed you love most. The perfect pair for pre-workout, post-practice and all the rest days in between. The days will be filled with walking comfort, without compromising good looks and style. This Birkenstock sandal is a genuine classic, emphasizing the handcrafted and natural look of stylish sandals. A comfort legend and a fashion staple. Narrow Width.