QO Load Centers offer premium features by allowing QO breakers, ground fault interrupters, arc fault interrupters, and surge arresters to be installed inside. QO Load Centers enable the use of a full complement of accessories. Systems are single phase and are rated for indoor use or are rain proof. QO Load Centers are designed for residential and industrial use to protect electrical systems, equipment, and people. This is a plug on neutral surge protective device for QO Load Centers. It is designed to protect electrical service and major household appliances, excluding electronic devices. Designed for 3 wire 120/240VAC single phase systems. This surge protection device is rated at 50 kA per phase. This surge protection device is UL Listed.