AfterPay Available - Celebrate 25 years of Merrell's women's specific fit with style and function. The uniquely engineered Merrell Siren 4 MID Gore-Tex cradles the specific contours of the female foot structure, providing long lasting cushioning, all day support. The Vibram high-performance rubber sole provides an unmatched durability and stability on the toughest of terrains while your feet are ensured to stay dry and fresh thanks to the waterproof Gore-Tex membrane and NXT treatment.