Model 350 Vibratone® horn produces a loud tone by the electro-mechanical vibration of a diaphragm. Its compact size, loud output and heavy duty construction makes the 350 ideal for industrial and institutional signaling applications. It's popularly used for general alarming, start and dismissal noticing, coded paging and process control in noisy areas. The 350 is enclosed in a zinc die cast housing and sealed with gray powder coat paint with a stainless steel diaphragm.