How to Add An SSD To The 27" iMac (Late 2015) - iFixit Repair Guide
iMac 17,1 replace pcie ssd - Apple Community
Original 512GB SSD MZ-JPU512T/0A6 For Apple iMac 21.5-inch A1418 Retina(Late 2013 – Late 2015), iMac 27-inch A1419 Retina(Late 2013 – Late 2015), Mac mini (Late 2014), Mac Pro (Late 2013), MacBook Air