Configure your own 21.5-inch Apple iMac (2015) at OWC
iMac 21,5" Late 2015, Quad-Core i5, 8 GB RAM, 500 GB SSD - Budapest
Apple iMac with 4K Retina display (21.5-inch, 2015) review: Apple packs more pixels into its smallest iMac - CNET
Amazon.co.jp: Apple iMac 21.5inch A1418 Late 2015 Integrated OS Monterey 12.6.5 5th Generation i5 16GB SSD256GB Wireless BT Camera 21.5" 4K(4096x2304) Bluetooth A08 : Computers