This is a standard thermal-magnetic breaker sized for branch-circuit protection in distribution panels, switchgear, and motor control centers. The 20 A rating handles lighting, receptacle, and light motor loads on a 480Y/277 V system.
For a panel-builder or MRO planner, the key fit check is the 20 A continuous rating at 480 V — this breaker sits in a 3-pole frame sized for 480Y/277 V systems. It's a fast mover for standard branch circuits: lighting panels, receptacle banks, small HVAC units. Keep one on the shelf if your plant runs ABB Relia-Gear switchgear; the 20 A frame is a common replacement size that turns over regularly.