It's the part you spec when you need motor overload protection in a compact S00 frame, Class 10 trip curve for standard motor starts, and spring-loaded terminals for tool-less wiring.
Class 10 trip means the relay will open within 10 seconds at 7.2× the set current — standard for most induction motor starts, but not for heavy inertia loads that need a Class 20 or 30. The 690 V rated value covers 400 V and 480 V systems with headroom; the power ratings at those voltages (2.2 kW at 400 V, 6.3 A at 480 V) tell you the motor size it protects in those line conditions. That saves a DIN slot and one wiring step per starter.
Mounts directly onto the contactor — no separate DIN-rail clip needed, though the S00 frame itself can be DIN-rail mounted if you're building a standalone overload block. The spring-loaded terminals accept 2× (0.5 to 2.5 mm²) solid or stranded, so you land two conductors per pole without ferrules.