What makes this Dell TH344 model NPS-420AB E power suppy so hard to find is the 10-pin Dell connector. Other than the 10-pin connector this 420 watt power supply is like most other atx power supplies. The TH344 is found in several mainstream Dell computers, namely servers like the PowerEdge 800 and PowerEdge 830. The difference between the Dell TH344 we sell and the one sold by others is that ours is brand new, never used. Most others stores offering this power supply offer it as pulled from a used computer.