Apple MK452LL/A iMac 21.5" AIO Desktop, 4K Retina Display, Intel Core i5-5675R Quad-Core 3.1GHz, 1TB SATA, macOS 10.11 El Capitan (Refurbished) This Certified Refurbished product has been tested and certified to work and look like new, with minimal to no signs of wear, by a manufacturer or specialized third-party seller approved by Amazon. The product is backed by a minimum 90-day warranty, and may arrive in a generic brown or white box.