Made from 100% Polyester Oxford which ensures the product is strong and highly waterproof. The cover is made using 3M Scotchlite Reflective Material which originates from the USA which gives high visibility in low resolution environments. The cover is ideal for regular sized backpacks, for up to 36L. From 2017 the chevron on the covers are made with reflective material to maximise protection for our customers. This backpack is designed for cyclists, so if you have a very large bag we recommend choosing the Navy Cover for Extra Large Backpacks as they cover backpacks up to 50L. Please take care when machine washing this product as the water-resistant properties can weaken.