The Siemens SENTRON 3VM9908-0BL10 is a shunt trip (auxiliary release) accessory designed for the 3VM molded-case circuit breaker family up to 630 A. It fires the breaker open on a 12 VDC signal, giving you remote trip capability for emergency-stop circuits, undervoltage protection schemes, or supervisory shutdown from a PLC or safety relay. The 4 kV surge voltage resistance means it handles the transients you get on a real industrial line without nuisance failure.
Mechanically, it clips into the left-side accessory slot of the 3VM breaker. The 25.7 mm width, 65.1 mm height, and 31.2 mm depth keep it inside the breaker's own envelope — no extra DIN rail space needed. Strip 10 mm (0.4 in) on the control wires for the spring-cage terminals. The coil draws up to 30 W at DC, so size your 12 VDC supply accordingly — a standard 24 VDC control transformer with a DC step-down is fine, but don't share the same 12 V rail that powers a PLC output card without checking the inrush.
Lifecycle status is Active per Siemens. No end-of-life notice or successor part number has been issued. This is the current-production shunt trip for the 3VM line — no last-time-buy scramble needed.