The Cisco 34-0773-03 is a 1100-watt AC power supply that is designed for use with the Catalyst 5500 series of switches. It is a reliable and efficient power supply that can provide plenty of power for even the most demanding systems. The 34-0773-03s- Cisco 1100-Watts Power Supply for Catalyst 5500 Series is a popular choice for Catalyst 5500 series switches because it is reliable, efficient, and quiet. It is also backed by a 3-year warranty from Cisco.