Like Dan says. Easiest way to tell what your frame takes is which side of the rim the lugs sit when the wheel is in place. If they are between the rim and the hub, then they will be a V-Brake as the brake pivots from the end of the arm. If they are on the other side of your rim, i.e. the rim is between your hub and mounts when you look at the bike from the side, then they are U-brake mounts as a U brake pivots half way along it's arm.