The ABB AF16Z-22-00-21 is a 4-pole contactor from the AF16Z series, with a dual-rated coil accepting 24-60 VAC or 20-60 VDC. That dual AC/DC coil range means one part covers both control supply types — useful when a panel has mixed control transformers and 24 VDC power supplies, or when you're standardizing spares across lines with different control voltages.
This is a DIN-rail-mount contactor, sized for standard 35 mm rail. The 4-pole configuration handles three-phase motor circuits plus a fourth pole for a neutral or auxiliary load. The dual-voltage coil simplifies wiring: one part for both AC and DC control buses, no coil-change needed when the panel design mixes supply types.