iMac (Retina 5K, 27-inch, Late 2015) - Technical Specifications
iMac SSD - 4mac
Indmem Ssd M2 Nvme M.2 256gb 512gb 1tb Ssd Pcie For Mac/macbook Air/macbook Pro Ssd Nvme Hard Drive 3x4 3d Nand Ssd For Apple - Solid State Drives - AliExpress
How-To: Now's the right time to swap your old iMac's hard drive for a fast new SSD - 9to5Mac
Reader's report: Installation of a 1 terabyte SSD in an Apple iMac 2013