the shape of stone lock is similar to the ancient copper lock, also known as stone throw, made of stone, small ten jin, large to 100 catties.
stone lock is a special method for the exercise of the arm, which can make the two wrist and buttocks increase the grip and swing of the power, is not the point of the point of the captain of the United States? This stone is heavier than the captain's shield! In practice, we should exchange hands alternately and practise with two hands.