The Siemens 3RT6916-1CE00 is a SIRIUS surge suppressor — an RC element sized for size S00 contactors and contactor relays. It clips onto the coil terminals of the contactor, suppressing voltage spikes when the coil de-energizes.
The 9 mm depth is the key dimension for panel integration — it adds almost no extra depth beyond the contactor body itself. Width is 28 mm, height 46 mm. That means it sits flush against the contactor face without protruding into the wiring channel or crowding adjacent devices on the DIN rail. The clip-on fastening method means no tools or additional wiring: it snaps directly onto the coil terminals of the S00 contactor. The RC element design is the classic solution for AC coils — it attenuates the inductive kick that can otherwise couple noise into nearby control wiring or damage solid-state outputs driving the coil. The 240-400 V AC voltage range covers the common control supply voltages in European and North American panels (240 V, 277 V, 400 V line-to-line).
Substance prohibitance per RoHS applies from 05/01/2012.