The QUANTUM is a departure from traditional running shoe design and construction. In the past if you've had foot problems, joint problems or are just looking for a softer, smoother suspension the QUANTUM is right for you. The basis for the QUANTUMs performance is a whole new approach - synergistically combining a new dual density, dual material midsole - firm ethyl vinyl acetate (for stability) over lightweight polyurethane (for conformance and shock absorption) - "wrapped" in an outsole of sticky FriXon AT rubber - to give you superior adherence on just about any surface. The resulting convergence of materials and tread design increase contact and spread the impact force over a greater area for greater traction and superior shock absorption. Select the men's and women's QUANTUM for you and your honey & take 10% off for ordering two pairs (or you can combine any Sportiva rock shoe & running shoe for the same deal)! Delivered anywhere in North America.