OWC - In-line Digital Thermal Sensor Cable for upgrading the Hard Drive in 27-inch & 21.5-inch iMac (2011) models : Amazon.co.uk: Computers & Accessories
DIY Bundle - 1TB OWC 6G SSD and HDD Kit for 21.5-inch iMac
How To Upgrade/Replace Mid-2011 iMac 21.5" Hard Drive To an SSD!
iMac 2011 27” SSD upgrade : r/iMac
2011 IMAC SAMSUNG 1TB 850 PRO SSD UPGRADE
OWC SSD Upgrade Kits For 27-Inch IMac 2011, 51% OFF