2nd HDD SSD Hard Drive Tray Caddy for 27" 21.5 iMac mid late 2009 2010 2011 2012 | eBay
HDD cable For Apple iMac A1312 27" 2011 desktop SATA Hard Drive HDD SSD Connector Flex Cable 593-1330 922-9875 - AliExpress
Replacing HDD with SSD in iMac 2010 | Yktoo
How-To: Now's the right time to swap your old iMac's hard drive for a fast new SSD - 9to5Mac
21.5" iMac Hard Drive SSD Upgrade or old drive replacement 2012-2017 (Including Retina) in 4k - YouTube
2011 imac 27" 32GB - final stage of 1TB + 2TB SSD upgrade (replaced HDD & optic drive). Also cleaned out the fans and case. Running 'SSD Fan Control' & 'Macs Fan
Further Explained: Apple's iMac 2011 Model Hard Drive 'Restrictions'
OWC Data Doubler - Replace Mac Optical Drive with an SSD