It's a 3-pole line-protection device built for distribution panels where high interrupting capacity is the deciding spec — 121 kA at 240 V, 75.6 kA at 415 V, and still 11.9 kA at 690 V. That kind of SCCR headroom means it can sit upstream of a fault-heavy feeder without cascading, which is what you want when coordinating a main breaker with downstream branch devices. The TM240 release is a fixed thermal-magnetic trip — no interchangeable rating plug, so the 125 A frame is what you get. That's fine for a dedicated feeder or a fixed-load panel where the ampacity isn't changing.
At 70 mm deep, 76.2 mm wide, and 130 mm tall, this MCCB fits the standard SENTRON 3VA footprint. The 76.2 mm width is a 3-module (3 x 25.4 mm) DIN-rail pitch — it snaps onto the rail without adapters.