DR-32 95 Uniform Coverage Horn by Atlas Sound is a Multi-Purpose Reflex Sound Horns for High Intelligibility Sound Distribution and Voice and Signal Applications an is exponentially-flared for an even and uniform sound distribution. It is convenient to use since it accepts all standard high efficiency compression drivers with 1 3/8" - 18 Male Threads. It is Weatherproof and made in all-metal that is made to last.