HP 865438-B21, 866793-001, is designed to allow for hot-plug and easy installation into HP ProLiant Gen10 Performance Servers. HP Flex Slot Power Supplies are certified for high-efficiency operation with flexibility to reduce overall energy consumption as well as power waste. HP 865438-B21 800W Power Supply is compatible with DL360, DL380, DL385, ML350, DL560, DL580 Gen10 Servers.