... steel telescopic tube.As displayed, its diameter can be limited in an extreamly small range.Features:1) Diameter: 0.25-50mm 2 ... ) Surface: Polished , annealed ,tempered7) Application: The products are widely used in precision instruments and apparatus, electronics, electric appliance and others 8 ... shaping.For more details, please make direct contact. Aluminium vacuum cleaner telescopic tube