This cable is used to connect a 5.25" CD-ROM DVD-ROM drive to your internal PCI or on-board soundcard. This will then allow you to plug your headphones or speakers into the 3.5mm jack connection to get full stereo sound from the front of your machine. No need to fiddle round with the back of your system anymore, this cheap and easy to install cable lets you take the hassle out of changing headphones / speakers on a regular basis. Standards: UL, CSA, ISO 9001:2000 manufacturer