The BIRKENSTOCK Sierra is the perfect sandal for those that are on their feet throughout the day and want shoes that provide exceptional comfort. The Adventure Crosstown is a sporty version of this model. It is designed with all adventurous and active BIRKENSTOCK fans in mind. The polyurethane sole is foamed onto the foot bed in two layers, which results in excellent non-slip properties, great flexibility and a long life. Wear yours with denim and indo western top.