The Siemens 3VA9908-0BD12 is a 24 VDC universal release accessory in the SENTRON line, designed as an auxiliary release for 3VA1 and 3VA20 through 3VA25 molded-case circuit breakers. It occupies three slots in the breaker accessory bay and draws up to 20 W at DC maximum, so the control transformer or DC supply feeding it needs to budget for that load. The part carries an overvoltage category III rating with 4 kV surge voltage resistance and pollution degree 3 — meaning it's rated for fixed-installation panels in industrial environments where transients and conductive dust are expected.
Physical footprint is 25.7 mm wide by 65.1 mm high by 28.8 mm deep — it nests inside the breaker's accessory cavity, not on the DIN rail, so it doesn't consume extra panel width. The stripped length for the connecting leads is 10 mm (0.4 in), which is standard for the screw-clamp terminals on the 3VA accessory bus.