Cable marking is essential and helpful when installing cables. This will ensure the right patch cords and cables are connected correctly to avoid unnecessary connection errors. The snap-on markers have numbers from 0-9 and letters from A-Z for applying easily and securely on both ends cables and patch cords. This provides positive identification and allows error-free installation of your critical systems. The marks are permanent and chemical resistant, and suitable for standard Ø3mm and Ø2mm cables and patch cords and other various cables.