How to Add An SSD To The 27" iMac (Late 2015) - iFixit Repair Guide
SSD Upgrade Kits for 27-Inch iMac (2012 - Early 2013)
Hard Drive Upgrade Kit for 27-Inch iMac 2012 - 2019
A-Tech 32GB Kit (4x8GB) RAM for Apple iMac (Late 2012, Late 2013, Late 2014, Mid 2015) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
iMac late 2012 SSD Upgrade - Apple Community
Apple iMac 21.5” SSD Upgrade (2013-2015) HDD To Solid State Drive (SATA) | Step By Step - YouTube
OWC 250GB Aura Pro 6G SSD for iMac (Late 2012)
OWC DIY Drive Upgrade/Install Kits for Apple iMac Models
OWC Complete HDD Upgrade Kit for Apple iMac 2009-2010
Timetec 32GB KIT(4x8GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 CL11 for iMac (Mid 2011, Late 2012, Late 2013, Late 2014 Retina 5K, Mid 2015 Retina 5K) SODIMM Memory Module MAC RAM Upgrade at Amazon.com