The kit supplies power to the drive, and can also put Hitachis into ModeB and can also eject your drive. Since the hardest part (for most people) is getting the drive into ModeB, this kit solves that problem. The kit will put the drive into ModeB no matter what, even if the drive is not connected to the computer at all. After the drive is in ModeB, you just need to have SATA that can handle ATAPI devices (CD/DVD Drives) and have the drivers installed. It should show up in Windows no problem, and then you can flash. Nearly all SATA controllers can handle CD/DVD drives, there are only a few SIL-based chipsets that do not.
Also, everybody should download this important safety information
concerning the correct use of the kit. Some people were frying their kits and/or drives with these kits. It has nothing to do with the kit itself, but more user error.