The Siemens SENTRON 3VA9908-0BB16 is an undervoltage release accessory designed for the 3VA1 and 3VA20 through 3VA25 molded-case circuit breaker families. Rated for 250 V DC and consuming 2.5 W at DC maximum, it's a drop-in auxiliary that mounts into the breaker's accessory slots without extra wiring harnesses.
At 28.8 mm deep by 25.7 mm wide by 65.1 mm high, this release sits inside the 3VA breaker's accessory compartment — no extra DIN-rail footprint needed. The three accessory slots on the breaker accept this unit; stripped length of 10 mm (0.4 inches) on the control wires matches standard ferrule or direct-wire termination. Overvoltage Category III and a 4 kV surge voltage rating mean it's built for the industrial panel environment, not a clean-room bench.