maxupgrades.com: Single SSD Drives kit for iMac 27 inch 2012 Models with SATA Blade SSD Module / Heatsink/ Power Cable and DATA Cables for [SSD + HDD] with iMac Adhesive LCD Tape
iMac Intel 21.5" and 27" (Mid 2011) SSD Upgrade Bundle - iFixit Store
Upgrade your iMac with OWC, 2017 4K Retina Edition | TweakTown