The ABB XT2LU3110BFF00NXXX is a current-limiting circuit breaker on the XT2 frame, rated 110 A with L-IR protection and a rotary mechanism. The L-IR designation means it combines a thermal-magnetic (L) overload element with an instantaneous (I) short-circuit trip and a separate (R) residual-current or ground-fault sensing block — a setup that lets you set the long-time pickup and short-time pickup independently for coordination downstream. The current-limiting action chops fault energy before it reaches let-through levels that would damage downstream components, which is the main reason you spec an XT2 over a standard MCCB in a high-fault panel.
Mounts on a DIN rail. The rotary mechanism extends through the panel door for a handle-operated disconnect.