The nickel plated connection for 14mm (AD) Hard Tubes from EK Water Blocks, is a compression fitting made of brass. It is in the colour nickel-silver and comes from the Classic series, which convinces by a simple design. In this fitting, the union nut serves as a compression ring that presses the sealing ring onto the hard tube. Thus it offers a higher safety and sealing than e.g. the fittings of the EK-HD series.