It's a 3-pole unit with a 100 A frame and a 20 A adjustable thermal-magnetic trip, so the breaker body is sized for up to 100 A but the trip unit is set at 20 A out of the box. That 20 A initial value is the continuous current rating; you can adjust it upward within the frame's range if the load demands it. The interrupting ratings are what make this part stand out on a high-fault panel: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3.7 kA at 690 V. That means you don't have to oversize the frame or reduce the trip setting when the panel runs hot — a real advantage in a crowded enclosure or a warm plant floor. Maximum power loss is 12.5 W at rated current, so the heat it dumps into the panel is modest for a 100 A frame.
A communication function is built in.