Genuine Dell 305w Power Supply PSU for Dimension 3100, E310, 5000, 5100, E510, 5150, E520, E521, and OptiPlex Towers GX320, GX520, GX620. Identical Dell part numbers: UH870 YH542. Identical model numbers: CX305N-00, CX305P-00 Genuine Dell Power Supply For Dell OptiPlex GX320, GX620 and Dimension 5100, E510, 5150, E521, E520, 3100, E310. 305 W Max Output. 100-127V or 200-240V Input. Dimensions: 6 W x 4 H x 5.5 D - Inches. Similar Dell Part Numbers: YH542 and UH870. Example Model Numbers: CX305N-00 and CX305P-00 Note: Buyer will receive any of the identical part numbers: YH542 or UH870 with the black label as shown.