EK-HDC Fitting is a solid-tube compression fitting, designed for use with solid tubing such as Acrylic, Copper, Stainless Steel or any other type of compatible hard tube. EK-HDC Fitting is a more secure variant of the EK-HD Adapter fitting as it prevents solid tube to be pulled out of the fitting by compressing the rubber gasket underneath the ring. The barb and the ring are made of nickel-plated CNC machined brass with quality O-rings. These fittings are fully compatible with EK-CSQ series (45°/90°) angled adapters. Best practice is to install these fittings using Allen Key 9mm (not included, available for separate purchase). Technical data: – thread: G1/4″ BSP; 4.5mm male thread lenght – supported tube: 16mm (OD) – outer diameter of a fitting: 23.8mm – installed height: 14.5mm – compatible tubing: solid Acrylic-, Copper-, Brass- or Stainless Steel tube ROHS Compliant! Made in Slovenia – Europe!