The Siemens 3RT2916-1CD00-ZX90 is a SIRIUS surge suppressor with RC elements, designed to clip onto size S00 contactors and control relays. It suppresses voltage spikes across the coil when the contactor or relay de-energizes, protecting nearby electronics and extending contact life. Rated for AC control supply voltages from 127 to 240 V at 50 Hz and 240 to 127 V at 60 Hz, and DC voltages from 150 to 250 V. The AC/DC input means one part covers both supply types within those ranges.
The suppressor clips directly onto the front of any SIRIUS size S00 contactor or relay — no tools, no extra wiring space needed. Dimensions are 28 mm wide, 46 mm tall, and only 9 mm deep, so it adds negligible depth to the device stack. The RC elements are rated for continuous duty at the coil voltage; verify the coil's VA rating does not exceed the suppressor's dissipation limits per the contactor datasheet.
The multi-unit packaging (ZX90 suffix) indicates it ships in a bulk pack, not single-piece retail. Factor that into your BOM line quantity and kitting process.