Features: The PTFE blue tubing outer diameter 4 mm, inner diameter 2 mm, density 2.15-2.20 g/cm3. PC4-M6 fittings- Made of copper and plastic, inner diameter(blue end) is 4mm. PC4-01 fittings- Made of stainless steel and plastic, inner diameter(black end) is 4mm. Connection through the external thread of the quick connection. Press and hold black or blue oval of quick fitting to release conveniently. Attention: These 3D printer accessories are small, please keep them away from children. Specifications: --PTFE Tube Color: Blue Material: PTFE (Poly Tetra Fluoro Ethylene) Outer Diameter: 4mm Inner Diameter: 2mm Density: 2.15-2.20 g/cm3 Heat Resistance: Up to 260 Length of Each Tube: 1m --PC4-M6 fittings Color: Golden + Blue. Inner Diameter (blue end): 4mm Material: Copper and plastic --PC4-01 Fittings Color: Black and silver Inner Diameter (black end): 4mm Material: Stainless steel and plastic Package Size: 14.2 * 10.0 * 2.3cm / 5.6 * 3.9 * 0.9in Package Weight: 85g / 3.0oz Package List: 3 * PTFE Hose(1M for Each Tube) 3 * PC4-M6 Fittings 3 * PC4-01 Fittings