Liquid Tight-Strain Relief Bushings & Plier Heyco Liquid Tight-Strain Relief Bushings are low-profile co-molded nylon and elastomer parts that function as a liquid-tight strain relief with a cable. These strain relief bushings can be pre-assembled to the cable before installation. The liquid-tight strain relief bushings meet UL strain relief requirements without bending or kinking the cable. These cable mount assemblies are available in multiple sizes for cable diameters ranging from 0.280' (7.1mm) to 0.440' (11.2mm).