The Eaton A30-30-10-42 is a 3-pole contactor from the A30 series, with a coil rated for 277V at 60Hz and 230-240V at 50Hz.
The 277V 60Hz / 230-240V 50Hz coil rating means the contactor's pull-in and hold-in voltage is designed for North American 277V lighting or control circuits at 60Hz, and European 230-240V industrial mains at 50Hz. This dual-frequency coil covers both common line voltages without a separate transformer tap.
