The Siemens 3VA9477-0GF20 is a 12" (300mm) shaft for a door-mounted rotary operator, part of the SENTRON accessory line. It's the mechanical link between the handle on the enclosure door and the breaker rotary mechanism inside — sized for the 3VA51/52/53/54 frames (125 A through 600 A) and the 3VA61/62/63/64 frames (150 A through 600 A).
Integration note
This is a mechanical accessory, not a breaker or switch. It mounts between the enclosure door and the breaker's rotary operating mechanism. The 300 mm length gives enough reach for standard-depth enclosures with the door-mounted handle on the front and the breaker on a sub-panel or DIN rail behind it. Verify the door cutout and handle interface match your enclosure before ordering — the shaft itself is the same across the listed frame sizes.