Packing: 2 pieces of rocker switches. The HY12-9 series rocker switch has six models: 1. HY12-9-2: (ON)-OFF, unilateral automatic reset function, the device is in the ON state when the button is pressed, and the button is automatically reset to the OFF state when the button is released. 2. HY12-9-3: (ON)-OFF-(ON), bilateral automatic reset function, press the button and the device is in the ON state, and release the button to automatically reset to the OFF state. 3. HY12-9-4: ON-OFF, press the button and the switch is in the ON or OFF state, and the switch keeps the original action after releasing the button. 4. HY12-9-5: ON-OFF-ON, press the button and the switch is in the ON or OFF state, after releasing the button, the switch keeps the original action. 5. HY12-9-6: ON-(ON), unilateral automatic reset function, this switch is also called universal transfer switch. This switch is generally only used for voltage commutation. 6. HY12-9-7: ON-OFF, press the button and the switch is in the ON or OFF state, after releasing the button, the switch keeps the original action.