The Siemens 3RV2021-0KA10-0DA0 is a SIRIUS 3RV2 motor starter protector in the size S0 frame. It's built for system protection without phase failure protection, with an A-release set at 0.9 to 1.25 A and a short-circuit release of 16 A. The screw terminal connections and standard switching capacity make it a straightforward fit for motor branch circuits in control panels. That 0.9...1.25 A A-release range is the overload protection window — it's what you size to the motor's full-load current. The 16 A short-circuit release handles fault clearing upstream of the contactor. For a small motor circuit, say a fractional-horsepower pump or a fan, this lands right in the sweet spot.
RoHS compliance dates back to October 1, 2009, and REACH candidate-list information is available from the manufacturer. Export control is straightforward: AL N / ECCN EAR99, no special licensing hassle for most shipments.
Panel integration
Size S0 snaps onto DIN rail — standard 35 mm profile. The packaging dimensions are 102 x 49 x 102 mm, so it doesn't eat much real estate in the enclosure. Screw terminals accept standard copper conductors; no special tooling needed.