The Logic behind Upper Body Layering The images below demonstrate the upper body layering system - how each piece works together as part of a larger system and the different choices of material. \\r\\n\\r\\nWhat Works This is the first layer of your system. Long sleeves are mandatory on the summit climb and upper mountain to protect your skin against abrasions should you slip or need to self arrest. This should be a quick drying, fast wicking, non-cotton, and comfortable top.