The Schneider Electric G12T3F80 is a GoPact MCCB 125 — a 3-pole fixed-mount molded case circuit breaker with a TM-D thermal-magnetic trip unit. The 80 A rating at 40 °C is the continuous current it carries without tripping in a 40 °C ambient; above that temperature you derate per the IEC 60947-2 thermal curve. The 10 kA breaking capacity at 380/415 V AC means it safely interrupts a fault current up to that level — enough for most distribution sub-feeders in a commercial or light industrial panel, but check your available fault current at the point of installation. The LI protection gives you thermal overload (L) and fixed magnetic short-circuit (I) curves; no electronic adjustment, so the trip threshold is set at the factory.
This breaker mounts to a backplate — not a DIN rail — so plan for screw-terminal lug connections on a panel sub-plate. Both upside and downside connections are front-accessible, which keeps wiring neat in a dead-front enclosure.