The Siemens 3VA1125-3EF42-0AA0-ZD00 is a 4-pole IEC frame 160 molded case circuit breaker with a 25 A nominal rating and a 25 kA breaking capacity at 415 V (class N). The TM240 thermal-magnetic trip unit gives overload adjustment from 18 A to 25 A and short-circuit pickup from 6.4 to 12.8 times In — so you set the Ir to match the cable ampacity and the Ii to ride through motor inrush without nuisance tripping.
The 4-pole footprint and nut keeper kit simplify installation for OEM builds, particularly for DC power applications in China where this variant is targeted.