The Omron J7KNAAR3124 is a 4-PST (4-pole, single-throw) electrical contactor, classified under Contactors and Starters. This is the part number you need for a BOM line or a swap — make sure the coil voltage and contact configuration match your existing circuit before committing.
A 4-PST contactor like this one is used to switch power to loads — motors, heaters, lighting banks — in a control panel. The 4-pole configuration gives you four independent switching paths, which is useful for three-phase plus neutral or for controlling multiple circuits from one coil.