Emerson Liebert iTON CX 600 VA Line Interactive UPS Emerson Liebert iTON CX 600VA is an outstanding UPS from the prestigious Emerson brand. This is a pure sine wave UPS designed to be used at homes and offices. The inverter gives an uninterrupted performance to the appliances which are connected to it such as the LED, LCD, personal computers, printers etc. The model has a long battery back-up.