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
Amazon.com: OWC SSD Upgrade Bundle for 2012-2019 21.5" iMacs, OWC Mercury Electra 1.0TB 6G SSD, OWC Express 2.5" USB 3.0 HDD Enclosure, Installation Tools and iMac Screen Adhesive Tape Set : Electronics