"WD AV-25 250GB SATA 3Gb/s 32MB Cache 2.5-inch 5400RPM AV Hard Drive" Low-power WD AV-25 (WD2500BUDT) hard drives are the cool, quiet and reliable storage choice for demanding always-on read/write applications. With a SATA 3 Gb/s interface, 32 MB cache and 250 GB capacity this 2.5-inch drive is ideal for DVRs, digital video surveillance and other small form factor environments where low power consumption and reliable operation are critical. 3-year limited warranty.