Atlas Sound","Model BIA-100 is the original reflex horn featuring a bi-axial design with twin air columns and exponential bell for wide-angle coverage with a linear frequency response.The horn provides excellent acoustic loading maintained to a 350 Hz low-frequency roll-off and optimizes delivery of high and mid-range signal levels.BIA-100 is designed for use with Atlas Sound PD Series compression drivers and models having 13\/8\" -18 male threads and 0.707\" dia. throat openings.The easily-mounted horn features the labor-saving patented gimbal-mount bracket assembly (U.S. Patent # 4,325,529) which allows for directional positioning up to 180° vertically and horizontally. It includes a steel bracket, cast-mounting base and provisions for flange installation.The weather-resistant, non-glare matte black foam horn is resistant to resonance.Bracket assembly is finished in durable epoxy.