ARRIS 20mm Outer Dia. 500mm 3K Roll Wrapped 100% Carbon Fiber Tube 18mm20mm500mm Matt Surface (2 PCS) 3K Pure Carbon Fiber, use for Multicopter, Helicopter Length: 500mm Outer Diameter: 20mm Inner Diameter: 18mm Package Includes: 2 pcs x 18mm*20mm*500mm carbon fiber tube (Matt Surface)