The Helios M 4 is a relay switch and comprehensive protection unit designed for two-speed three-phase fans featuring built-in thermal contacts. Encased in a durable light grey polymer housing with an IP55 protection rating, it is suitable for surface mounting. Operation is controlled via a 3‑step switch marked “0−1−2,” allowing easy speed selection. The device includes a control lamp for status indication and requires manual restart after a fault by switching to position “0,” ensuring reliable and safe fan operation.