Water-cooled hard tube hollow Material: This extension tube is made of high quality Chrome-vanadium Steel with a chrome finish and is durable, durable and rust free. corrosion resistance and oxidation resistance. tubes Seamless Construction: The interior is smooth with no seam and is available in an extruded structural or a drawn seamless aluminum round tube for precision applications. The aluminum tubing can be polished. Long tube Size: Outside diameter: 15mm Round Tube Great for: Commonly used in DIY projects, hobby, crafts, building model, home decoration, frames, industry, gardening products and more. round tube hollow Package Include: 1pcs×Seamless Steel Pipe, Manufacturer: ACVACV