OWCDIYIMACHDD12, OWC Complete Hard Drive Upgrade Kit Including Tools for all 27" iMacs 2012 & Later | EET
SSD Upgrade Kits for 27-Inch iMac (2012 - Early 2013)
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