PU note book ring mechanism 1.durable and convenient 2.Competitive price ,high quality and excellent service 3.Waterproof 2 ring mechanism We offer whole set of 2,3,4,5,6, and multi ring metal clips,ring mechanism O,D,Q shape Different specifications are available according to customers' requirements.We produce all kinds of stationery file clips: ring mechanism, lever arch file, file clip, file ...