This item is in good condition and has been tested working. Please refer to the stock photo to insure the item will work for your application. This item is Dell part number YH542 (or a compatible part number).    

Dimension (Tower): 3100, 5000, 5100, 5150, E310, E510, E520, E521
Optiplex (Tower): GX280, GX520, GX620
305 Watt Power Supply
1 x 24-Pin Standard ATX Power Connector
1 x 4-Pin ATX CPU Power Connector
1 x Floppy Disk Drive Power Connector
2 x Molex Power Connectors
2 x Sata Connectors
100-120V or 200-240V Input  
Tested good working
Grade - A
Dell Part Number: YH542 (or a compatible part number)