It carries a TM240 thermal-magnetic release, meaning the thermal element is fixed at 240 A frame rating with adjustable magnetic pickup; the breaker itself is rated 125 A continuous at 40 °C ambient, and that current holds flat up to 50 °C before the thermal derating curve begins (122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, 114 A at 70 °C). For a panel builder, that means you can load it to 125 A in a ventilated enclosure without worrying about nuisance tripping until the ambient climbs past 50 °C. Breaking capacity is where this part earns its place in high-fault installations: 187 kA at 240 V AC, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V.
Three-pole, 76.2 mm wide (3 inches), 130 mm tall, 70 mm deep. The breaker ships without an undervoltage release or shunt trip (no voltage trigger, no trip indicator), so if the spec calls for remote tripping, you add the 3VA auxiliary switch block — the design accepts up to three auxiliary switches HQ.
Maximum power loss is 28.1 W at rated current. In a sealed, non-ventilated enclosure with multiple breakers, that heat adds to the internal temperature rise — factor it into your thermal calculation if the panel ambient approaches the 70 °C operating maximum.