877-G1 EDWARDS SIGNALING Horn, Weatherproof 77-G1 is a low-current high decibel Vibrating Horn for heavy-duty use and is UL listed to NEMA 4X enclosure requirements. The die-cast weatherproof box has a durable, corrosion-resistant, electrostatic heat flowed powder epoxy gray finish. It is used for indoor applications. Mount on conduit or to any flat surface. A hole on the top has been drilled and tapped for 3/4-inch (19mm)-14 NPT conduit. Knockouts are located on the bottom and rear of the unit.