Washing your sleeping bag liner when travelling isnt always practical which means they can start to smell a little unpleasant after a while however this one is treated with permanent axp anti bacterial technology which reduces the growth of bacteria that cause smells and mould this mummy shaped liner is made from 100 cotton for optimum comfort and breathability in warmer climates and includes a hidden pocket for storing your phone and other small valuables the liner also comes with a pil