Serial ATA is the next generation of ATA technology, replacing the current standard (parallel ATA, also know as Ultra ATA 66/100/133). This next generation offers data transfer speeds of up to 1.5Gb/sec (150MB/sec) and addresses many of the limitations of the current parallel ATA technology. In addition, Serial ATA maintains 100% compatibility with today's software, meaning that no changes are necessary in existing operation systems or drivers and is designed to offer the same cost effectiveness as Parallel ATA, offering the highest performance at the lowest cost.SIIG Serial ATA-to-Ultra ATA (Parallel ATA) adapter allows you to connect existing Ultra ATA 133/100/66 hard disk drives to the latest Serial ATA host adapter. It plugs into the 40-pin connector of your Ultra ATA hard disk drive directly no PCI-slot is required. This adapter is compatible with various brands of Serial ATA host adapters including SIIG and many other brands.