Amazon.com: OWC 8GB (2 x 4GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S08P) : Everything Else
Apple iMac 5K Retina 27" Desktop - 3.2GHz Quad-Core i5 - 8GB RAM - 1TB – The Refurbished Apple Store