Sizes Lever Snap Hook Overall Length: 41mm (height) x 30mm (width) Inner Diameter: 8mm (height) x 26mm (width) Wire Diameter: 2mm Ami Snap Hook Overall Length: 41mm (height) x 31mm (width) Inner Diameter: 8mm (height) x 26mm (width) Wire Diameter: 2.5mm The included backpack rings are sized to be used in combination with the snap hooks. They are sized to allow a 20mm wide tape to pass through. Since the snap hooks and backpack rings are a set, you can create an adjustable shoulder strap. I will be gradually listing unused materials(*´-`) I will be listing them at a lower price than when I purchased them, so please consider them☆ There are also bulk discounts available. Please feel free to contact me. Although they are new and unused, Please purchase them if you understand that they are stored at home☆