The Mercury 35NO-24ATH Relay is used to open and close circuits in applications with inductive (motors) and lighting loads. The "H" at the end of the manufacturer part number designates that this relay is back-filled with hydrogen, which is what makes it ideal for inductive or lighting loads. This relay is hermetically sealed with high-quality glass to metals seals. The stainless steel tube is completely encapsulated in high-grade UL approved epoxy that prevents moisture damage and voltage breakdown.