This clamp is used for preventing your drawstring bags from sliding off your shoulders if you are running or even walking. Put the two strings into each of the circles after you have the bag on. It tightens the two strings towards your breast so it would not slide off from your shoulders and let you run smoothly without holding the strings down to prevent it sliding off your shoulders. It is quite useful and I remember I saw this once somewhere but I cannot find it online so I create one myself, hope it is useful for you.