OWC's DIYIMACHDD12 in-line solution is the only hardware digital thermal sensor on the market allowing a third-party SATA drive to be installed in your iMac. A convenient, plug-and-play cable, the In-line Digital Thermal Sensor eliminates fan noise and maintains proper system fan control through the iMac's System Management Controller. This innovative device is designed specifically for the iMac, requires no software hacks and ensures compatibility with Apple's built-in diagnostic processes. Using an OWC Internal HDD DIY Kit (sold separately), replace your iMac's original hard drive with a high-capacity hard drive or a lighting fast SSD with a NewerTech Adaptadrive, for dramatic upgrades in storage capacity or data speed while maintaining the original system's fan and diagnostic performance.