By Bestbuy.com

OWC - 64GB (4x16GB) PC4-19200 DDR4 2400MHz CL17 260pin SO-DIMMs Memory Compatible with Select Mac Models

4 x 16 GB (64 GB) PC19200 DDR4 2400MHz SO-DIMM Memory, 260-Pin, 1.2 Volts, Non-registered, Non-ECC, Fully compliant with JEDEC specifications, ROHS compliant, warranty safe upgrade, CYCLE TIME: 0.83 ns, TIMING: CAS = 17.0, Full Parameters: 17-17-17-14, BANDWIDTH: 19.2GB/s, Low noise 8-layer PCB Program, Compatible with 2017 iMac: iMac w/Retina 5K display (27 inch mid 2017) Model ID: iMac18,3 (3.4GHz & 3.5GHz & 3.8GHz Core i5 & 4.2GHz Core i7) , Compatible with select PC Laptop, PC Notebook, & All in One Computers