Grease, fuels, LP and natural gas (available on special order), refrigeration, instrumentation and hydraulic systems. "L" at the end of a part# means light pattern - these fittings are completely interchangeable with full pattern fittings, but have been modified in some way. This modification is usually in the Length of the pipe threads. Used in plumbing and light industrial applications. Meets specifications and standards of asa, ASME and SAE.