Loc-Line® is sized by the smallest hole through the part. As an example a quarter inch rod will fit through a Quarter Inch part. Most customers find it convenient to measure the largest outside diameter of the parts. We offer the following image to help you determine what size of Loc-Line you need. All information contained in this file is the property of Lockwood Products Inc ®and my not be displayed or published without written permission from Lockwood Products Inc ®