- Headquartered in a new 22,000 square foot facility in Indianapolis, Indiana, Mallory Sonalert Products, Inc. is a leader in the manufacture and development of Sonalert® electronic audible signal products. The company has made its trademarked Sonalert line for over thirty years. In addition to sonalert products, Mallory also distributes a full range of audible signal devices including transducers, indicators, sirens, buzzers and related hardware to a broad range of customers in industrial, military and consumer electronic markets.