I just received this wonderful pack. Exactly the right size for my needs and fantastically well made. However, there is a feature that I can't figure out. On the top of the highest middle pocket, there is a kind of a double loop. It is about 3/4 inch wide webbing, with a small fixed and sewn in loop. Right on top of this loop is a larger loop, roughly 2-3 " tall which is closed with a snap. Does anyone know the purpose of these loops?