How to add a fast new SSD to your old Mac or MacBook for only $150 - 9to5Mac
OWC Internal SSD DIY Kit For All Apple 21.5" iMac 2011 Models w/ Tools
Apple iMac 21.5” SSD Upgrade (2013-2015) HDD To Solid State Drive (SATA) | Step By Step - YouTube
Amazon.com: OWC SSD Upgrade Kit for 2011 21.5-inch iMacs, Mercury Electra 250GB 6G SSD, 18" SATA III 6Gbps Data Cable, Installation Tools and iMac Screen Adhesive Tape Set : Electronics
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OWC DIY Kit for all Apple 21.5 "iMac 2011 Models for installing an internal SSD. Without tools. (Compatible models: iMac 21.5 inch 2011) Security Locks & Accessories - Newegg.com
OWC SSD Upgrade Kit iMac 21.5“ 2012-2019 - Tools only