Jaw crushers are referred to by two sets of numbers, the first being the opening size of the jaw; the second being the width. So, a “1036” jaw would accept a 10″ boulder at the top and be 3′ wide. If the pit where the jaw is being used has river rock which does not exceed 10″ in size then this size crusher would be acceptable. Larger crushers are better choices when the average size is larger, such as where rock is blasted using explosives. The width of the jaw directly impacts its throughput rate.