Climbing Rope Gauge This climbing rope gauge is the perfect accessory for helping you determine the size of your rope. Made of solid stainless steel, the rope gauge is designed to withstand tough working conditions. While its exceptional resistance to corrosion makes it a good choice when working in damp environments, such as rigging or marine work. The climbing rope gauge covers sizes 10.5mm, 11mm, 12mm &and13mm, and it’s very easy to use too. You can use the gauge to measure the length of your entire rope through the various holes provided. Or, you can slide it over the top at any point too.