That's not a defibrillator, it's OWC's DIY SSD kit for 2011 iMacs - 9to5Mac
OWC SSD Upgrade Bundle for 2011 iMacs, OWC Mercury Electra 120GB 6G SSD, AdaptaDrive 2.5" to 3.5" Drive Converter Bracket, in-line Digital Thermal Sensor Cable, Installation Tools, (OWCKITIM11HE120) : Electronics
OWC Digital Thermal Sensor for 2009-2010 iMac HD Upgrade
How-To: Now's the right time to swap your old iMac's hard drive for a fast new SSD - 9to5Mac
In-Line Digital Thermal Sensor HDD Upgrade Cable for iMac 2011, (DIDIMACHDD11), Includes cables necessary for drive installation into main drive bay of Apple.., By OWC - Walmart.com
OWC DIY Drive Upgrade/Install Kits for Apple iMac Models
2011 IMAC SAMSUNG 1TB 850 PRO SSD UPGRADE - YouTube