16GB ( 1 x 16GB Module ) DDR4 2133 MHz ( PC4-17000 ) DDR4 SO-DIMM ( 260-Pin ) Non-ECC Unbuffered Apple Mac Certified Memory RAM Upgrade Designed For Select Apple Mac Systems: iMac (for a complete list of compatible systems, see the description section) Compatible Apple Order Numbers: MMQA2LL/A Compatible Apple Model IDs: iMac18,1 Compatible Apple Model Numbers/EMC: A1418 (EMC 3068) A-Tech provides a Lifetime Warranty for all orders & offers complimentary United States based Tech Support before, during, & after your purchase