100% cotton, brushed on the body side for strokable softness; the side in the tail is smooth, almost like sateen. (This is also inside in the body of the sling, for ease of adjustment.) Its light weight makes it ideal for warmer climates, while giving it a drape one doesn't usually find in twills. As a sling, it can be as plain as you like, or consider it a blank canvas for a tail accent