Cambium is the layer of a tree between the bark and the wood. What could possibly describe the first canvas softshell jacket any better? By bonding 10oz cotton canvas with polyester fleece, you get all the durability of a canvas jacket in a lightweight package. Stretch underarm gussets enhance mobility and breathability and deliver the first canvas jacket that doesn't feel like a straight jacket! Add in 4 zippered pockets and a Teflon® coating for oil and water repellency, and you get the baddest canvas jacket ever produced. This is a streamlined fit that mirrors most softshell jackets so order accordingly.