The Siemens SIRIUS 3RT1944-5AR62 is a replacement magnet coil for Size S3 contactors, wound for 400 V AC at 50 Hz and 440 V AC at 60 Hz control supply. It uses spring-loaded terminals for the coil connections — a detail that matters if you're swapping out a screw-terminal coil on a live rail: the spring cage grabs the stripped wire, no screwdriver torque needed, but you'll need a small flathead to press the release slot if you mess up the strip length.
The coil draws its listed inrush and holding VA from the control transformer; the spring-loaded connection accepts solid or ferruled stranded wire typical for control circuits. The coil snaps onto the Size S3 contactor magnet system — no tools for the mechanical fit, just align and press. Mounts on the same DIN rail as the contactor, so no extra panel space needed.