Riddonkulous

I hold things together without a knot or glue, A tiny metal grip that quietly does what I do. I pinch what is loose and keep it in place, Then vanish in pockets without leaving a trace. I can bind up your papers or secure up your bag, I am simple and small, yet helpful each day. I am found in many rooms and in many a pack, Turning disorder into something that stays neatly stacked. I can snap, I can clamp, I can close, I can keep, I am quiet and strong while I do all I climate. What am I, useful and plain in my role, A little helper that gathers the whole so it holds?