EK-Loop HD Tube is solid type extruded acrylic tubing intended to be used with EK-HD Adapter fittings. The tubing may be heat treated to achieve certain bends. For expert users only!It is mandatory to chamfer the edges of freshly cut tube in order to prevent gasket (O-ring) damage. EK recommends a 0,5mm x 45 chamfer.Specification:- Inner diameter: 12 mm- Outer diameter: 16 mm- Length: 500 mm (19.5\")The package contains 2 pieces of tube only. Please purchase EK-HD Adapter fittings separately!Made in Slovenia EU!For easier installation we recommend wetting the gasket (O-ring) using drops of water prior to installing solid tube.