21-Inch Apple Studio Display (Graphite - CRT) Specs: EveryMac.com
Apple iMac A1311 21.5" Desktop MC309LL/A (May, 2011) for sale online | eBay
Amazon.com: Apple iMac 21.5in 2.7GHz Core i5 (ME086LL/A) All In One Desktop, 8GB Memory, 256GB Solid State Drive, MacOS 10.12 Sierra (Renewed) : Electronics