The OWC in-line digital thermal sensor is a temperature sensor cable for the Apple iMac. The in-line digital thermal sensor cable 2011 models suitable for the iMac. It is required for all installed in the main drive bay drives. It maintains the correct system fan control, if one is upgrading late 2009- 2010 iMac models. The iMac HDD upgrade option is certified for the Apple Hardware Test. It addresses issues with firmware incompatibilities with hard drives Drittanbietern.erfordert no software hacks and provides compatibility with the integrated diagnostic processes of Apple.