PEAK's unique straight coil design causes the spring coils to form an inverted "oeV", resulting in a better experience than working with a conventional wrapped spring. PEAK's straight coil has parallel slits which will hold your materials evenly and more securely. The PEAK Material Clip will fit '1/4 inch diameter shafts. Clips will rotate to any angle needed, and multiple Material Clips can be used in tandem. PEAK's Material Clip is provided with 2 sizes of coil to grip a wider range of materials better.