The Siemens 3VA9334-0SB20 is a cover frame sized 183.6 x 109.3 mm (WxH), designed as an accessory for a 4-pole circuit breaker in the 3VA5 series with TMTU access, covering the 400/600 A frame range.
The cover frame snaps onto the breaker front, so no additional DIN-rail space is consumed — it stays within the existing panel footprint.