Part No: AC26400 - Western Digital Caviar 6.4GB 5400RPM EIDE Dma/ATA-66 (ultra) 40-Pin 3.5-inch Low Profile (1.0 inch) Internal Hard Drive

Capacity: 6.4 GB
Form Factor: 3.5 inches (standard size for desktop hard drives)
Interface: EIDE (Enhanced Integrated Drive Electronics) DMA/ATA-66 (Ultra ATA/66), which allows for data transfer rates up to 66 MB/s
RPM: 5400 RPM (Revolutions Per Minute), offering moderate performance
Profile: Low Profile (1.0 inch thick), making it slightly thinner than standard drives, which might be useful for specific space-constrained applications