SL4-120-RBKK-CR by Danaher

The SL4-120-RBKK-CR is a modular stack-light assembly produced by Danaher within its Timers and Controllers series. It provides visual status indication on automated equipment where audible alarms are not practical. This four-segment device mounts to machines or control panels and gives operators a clear, color-coded view of process states, faults, or material calls, thereby shortening response time in industrial automation.

The tower operates from a line supply of 120 VAC, allowing direct connection to standard control transformers without additional power conversion. Each lamp draws 6 W, so current demand is predictable and can be fused accordingly. Wire termination is through copper conductors that exit the base as flexible leads, and the service tails measure 18 in, providing enough length for routing inside small enclosures. The tower has exactly 4 separate lenses, allowing discrete machine states to be assigned to individual colors. The steady illumination mode avoids flashing circuitry and ensures continuous visibility. The wire-lead connection style simplifies wiring because no terminal blocks are needed. The wiring insulation withstands 300 V, matching most control-circuit protection devices, while the copper conductors support low-resistance signaling.

The lens stack follows an order of red, blue, black, and black. The first two sections present active colors, while the two black sections accept user-installed filters or opaque caps when only dual indication is required. The ambient operating temperature ranges from -25 °C to 45 °C, enabling operation on unconditioned factory floors. The internal PVC insulation has a continuous temperature rating of 105 °C, so conductor heating from inrush currents remains within safe margins. With an overall height of 14 in, the beacon remains visible above most guards yet fits inside standard 600 mm cabinets. A chrome-finished top cap resists corrosion and adds mechanical strength at the mounting stud. The copper wiring and steady-light electronics support signaling during extended duty cycles.