This is a thermal sensor for the 2011 iMac, both the 21.5 inch and the 27 inch models. This unique cable is a plug and play solution for the fan noise that happens when you remove the original Apple thermal sensor. Part of upgrading or replacing the hard drive in this family of iMacs is the thermal sensor is disconnected. The immediate response from the iMac is to turn the fan on full speed. Basically it thinks the sensor is broken, which is, and so to provent the hard drive overheating, it turns the fan on maximum. Until you have experienced ths, you have no idea how annoying ... and loud it is!! There are two solutions 1. OWC Thermal Sensor cable (this product) This cable goes between the drive SATA connection and the main board SATA connection. There is a snesor pad you stick onto the drive that monitors the temparature. This is a cable only. Does not include an SSD or any parts you require to replace your iMac drive. You can read our guide on installing an SSD in your iMac here The cable has been designed for the: Mid 2011 iMac 21.5 inch (iMac12,1) Mid 2011 iMac 27 inch (iMac12,2) And the alternative option? 2. SSD Fan Control software I dont want to do us out of a sale, but there is a free solution, and it is one we have used for ten years, in hundreds of upgrades, without any issues. It is a free app called SSD Fan Control. It does not live in the app store (for obvious reasons), it is a naughty third party app Apple does not want you to know about. Click on the link above, download and install. Reasons NOT to use SSD Fan Control The main reason is it by passes Apple's SMC thermal sensor system. OWC also mentions that their cable solution passes the AHT (Apple Hardware Test). We have never had an issue with a new SSD and the AHT. Reasons to use SSD Fan Control This software has three settings: Manual, Auto and SMART. SMART stands for Self-Monitoring Analysis and Reporting Technology. All the SSDs we sell, particularly the Crucial SSD have inbuilt SMART. This means they report on their health and operating conditions. SSD Fan Control uses this technology. As long as your SSD is reporting the correct temperature via SMART, it will set the fan correctly. Even better, you can set what the fan does based on the temperature. Have we talked you out of this product? If not, it is a very clever piece of hardware, and no matter what additional software you use, nothing beats using the inbuilt Apple system.
