Water-cooled hard tube hollow Material: This extension tube is made of high quality Alloy Precision Steel with a chrome finish and is durable, durable and rust free. corrosion resistance and oxidation resistance. aluminum 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: ID-10mm , ID-9mm , ID-8mm , ID-7mm , ID-6.7mm , ID-6mm , ID-5.5mm , ID-5.4mm , ID-5mm , ID-11mm , ID-5.45mm , ID-8.2mm , ID-12mm , ID-13mm , ID-14mm , ID-10.5mmOD16mm-500mm-long; Feature:Hydraulic alloy precision steel tubes seamless 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