The Siemens 3RT1016-1VB41 is a SIRIUS power contactor in the compact Size S00 frame — 45 mm wide, 57.5 mm tall, 72 mm deep — designed for screw and snap-on mounting onto 35 mm DIN rail per DIN EN 50022. Rated for the main circuit at AC-2 duty (4 kW at 400 V) and AC-4 duty (8.5 A at 400 V), this contactor handles motor switching for pumps, fans, and conveyors within its frame size. The screw-type terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or up to 2x (0.75 to 4 mm²) — solid or stranded — which covers the common panel wire gauges for this class. The auxiliary contact block is a single instantaneous contact rated at 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V. That one N.O. or N.C. contact (the evidence doesn't specify which) is enough for a feedback signal to a PLC or a holding circuit interlock — but if you need more auxiliary poles, you'll add a side-mount block.
These numbers matter when you're sizing the branch circuit protection in a panel — the 20 A limit for Type 2 is the one most panel builders target to avoid replacing the contactor after a fault.