Braided carbon fibre tube/sleeve can be used as reinforcement for tubular forms including making or reinforcing carbon fibre tubes/frames. This small diamater braid, sometimes known as bootlace, has a nominal diameter of just 5mm (with the weave at 45°) but can contract down to 3mm or expand up to 7mm diamater.
Woven from lightweight 3k fibre at 400gsm. Sold by the linear metre.