Allen-Bradley 855T-B10DC4 Stack Light Piezo Sounder

Allen-Bradley 855T-B10DC4 is a 70 mm stack-light module that combines a red indicator light with a built-in piezo sounder for audible signaling in industrial control towers. Designed for 120V AC operation, this black-housing unit (70 mm diameter) is a combined light-with-sound module in the 855T Series, compatible with standard 855T mounting bases and stack configurations. The red lens provides an immediate visual cue, while the piezo buzzer adds audible alert to attract operator attention in noisy environments. The variant uses incandescent illumination in this model, producing a steady light with tone to accompany the audible alert. Typical applications include machine fault indication, process alarms, and status signaling on production lines, packaging, and automation panels. The 855T family consolidates these signals into a compact module suitable for easy integration into control towers, enabling quick status recognition without separate devices. Key specs for this part include 70 mm size, red housing and lens, incandescent steady illumination with integrated piezo sounder, and 120V AC operation (voltage code 10). For buyers updating legacy 855T signaling setups, this red 855T-B10DC4 offers a direct replacement that preserves the familiar form factor and signaling behavior.