Abstract: A snap-hook for use with ropes or the like, primarily for rock-climbing, made up of a body or hook in the shape of a "C" of which the straight rear central portion is extended by two curved arms, one upper, the other lower, of which the free ends are joined, on closing the snap-hook, by a pivoting finger moving on one of these two ends, said snap-hook comprising an internal periphery having an essentially semi-circular cross-section and an external periphery which is formed, on at least the whole length of the upper and lower arms, of a rib of uniform section, designed to increase the rigidity of the said upper and lower arms, without increasing, and even lightening, the weight of the snap-hook.