Abstract: A chock for mountain climbers is in the form of a truncated pyramid having sides of unequal width so that the chock is readily conformable for secure wedging engagement virtually in any type of crevice, the chock being manufactured in different sizes according to variations in size of cracks or crevices encountered in mountain climbing. The configuration permits central placement of one end of a carabiner, the opposite free end of which is provided with a hero loop to permit fastening of a ring for direct connection of the climbing rope thereby obviating connection of an additional carabiner.