The Ideal-Air Pro-Dual Outdoor Unit can me matched up with multiple indoor head configurations. These systems are designed to function with 1 single outdoor condensing unit with a minimum of 2 indoor units up to 4 indoor heads maximum. (See Match up chart online at www.ideal-air.com; this will also be listed on the packaging of the box). 208?230 V, 1ph, 60 Hz, 25 Amps and 1970 W. Outdoor ambient cooling operating temperature range -13øF to 122øF, outdoor ambient heating operating temperature range -13øF to 86øF. Line set size depends on the indoor wall mount or ceiling evaporator head.