Yes, that's the one you need.
Be aware that not all USB memory devices work on the xbox. The size must be smaller than 4 gigabytes.
Modern pc's use SATA cables to connect their harddisk. The older ones used PATA which is a 40 or 80 ribbon flatcable.
If your pc uses the 80 wire cable, you can use your xbox 40 wire cable to connect the xbox harddisk to the pc.
If your pc only has one PATA connector, things get complicated to perform a hotswap.
regards.