The ABB XT1HQ3050AAA000XXX is a molded case circuit breaker from the XT1H family, built on a 125 A frame with a thermal-magnetic fixed (TMF) trip unit adjustable from 50 to 500 A. It's a 3-pole unit with line and load side lugs, listed for UL and CSA markets.
The TMF trip unit covers a 50–500 A continuous current range, which suits it for feeder protection or large motor branch circuits where you need adjustable overload and fixed short-circuit response. The 125 A frame size keeps the physical footprint compact relative to the trip range it can handle.