Ek acf fitting advanced compression fitting is a soft tube compression fitting designed for use with flexible soft tubing such as pvc epdm norprene silicone or any other type of compatible flexible tube ek acf fitting is a more secure variant of the tubing connector as the locking ring prevents the flexible tube from being pulled out of the fitting the barb is made of nickel plated cnc machined brass and the ring is made of anodized cnc machined aluminium the fittings feature quality rubber o