Direct replacement for 4XX1H, J6J6M, AC550E-S0, DH550E-S0 550W non-hot-swap PSU.; Fully compatible with Dell PowerEdge R320, R420, R520 rack servers.; Stable 550W output with 100-240V universal input and active PFC.; OEM-matched connectors and size for direct plug-and-play installation.; Built-in OVP, OCP, SCP, OTP protections for reliable server operation.