Apple
Documentation
iMac (Retina 4K, 21.5-inch, Late 2015)
Year introduced: 2015
Tech Specs
Documents
iMac (Retina 4K, 21.5-inch, Late 2015) - Quick Start Guide
iMac (Retina 5K, 27-inch, Late 2015) - Essentials
macOS User Guide
iMac (Retina 4K, 21.5-inch, Late 2015) - Information Guide