The Siemens 3VA9137-0FK47 is a door-coupling rotary operating mechanism from the SENTRON accessory line, designed specifically for 3VA4/5 125 frame molded-case circuit breakers. It's the hardware that lets you mount the breaker deep in the enclosure while the rotary handle lives on the door — standard practice for emergency-off stations and disconnect points where you need the operator accessible from outside a closed panel.
Rated IP65 and NEMA 4, 4X, so this operator survives washdown environments and corrosive atmospheres. The 77 mm width and 70 mm height are the cutout dimensions the door needs. That's a compact footprint for a 125 A frame operator — leaves room alongside for pilot devices or a local E-stop pushbutton on the same door. This version includes the door interlock, a 24 V DC lighting kit, and a door-open position accessory. The interlock prevents opening the door with the breaker closed — a safety requirement under many local codes. The lighting kit backlights the handle position so an operator can read ON/OFF status from across a dim pump room.