The contact ratings are voltage-dependent: 1 A at 24 V, 0.2 A at 125 V, and 0.1 A at 250 V — so the 3 A maximum only applies at lower voltages; at typical control voltages (120 VAC) the actual switching capacity is lower. Coil pickup is 100–127 V at 50/60 Hz, with a dropout threshold around 85 % of rated voltage (0.85 initial value), and a recovery time of 150 ms before the coil can re-energize after drop-out.
Clip-on fastening means it snaps directly onto the front or side of a SIRIUS contactor without tools — no DIN rail footprint consumed, but it does add 45 mm width and 75 mm depth to the contactor envelope.