The ABB 1SDA068164R1 is a 3-pole breaking part in the XT2S 160 frame, rated Iu 160 A continuous current. This is the interrupting section of the molded-case breaker — the part that opens the circuit under fault — not the complete breaker assembly.
The Iu 160 A rating sets the continuous current the breaker's thermal-magnetic trip unit will carry without tripping. For selective coordination studies, you'll want the Ics (service breaking capacity) from the full breaker datasheet; this breaking part alone doesn't carry that number.