Its AC-1 rating of 35 A at 24 V AC, 50/60 Hz defines the resistive load it can switch continuously — think heater banks, lighting, or transformer primaries, where inrush is minimal. The 4 NO main poles give you four independently switched circuits, all normally open. The integrated auxiliary contact block (1 NO + 1 NC) handles feedback or interlocking without a separate add-on.
Size S0 is the standard footprint for this current class on a DIN rail. The 50/60 Hz rating means it works on either line frequency without derating.