If you have got one of the Dell models below and an ordinary atx power supply you are going to need this adapter. The Dell proprietary models listed below have a different wiring configuration than normal atx power supplies which is why the adapter is necessary. This adapter takes a normal atx 20 pin connector, converts it to the Dell proprietary connector, and also provides the Dell P10 AUX connector. Aka Athena Power Cable-Dell-X. THESE ARE DISCONTINUED AND ALL GONE- PLEASE DO NOT ORDER.