Healthy Back bag in Black textured nylon. Size Medium - Hardwearing, machine washable, water resistant... Just some of the properties of nylon. These Medium sized bags provide a roomy 10 litre capacity and are robust and lightweight which makes them perfect for an active lifestyle. A new tablet protective pocket has now been added to this great bag. Your tablet, kindle or netbook fits comfortably inside your bag, keeping your gadgets safe on the go!