Samsung 4 GB SO-DIMM DDR4 2666 MHz (M471A5244CB0-CTD) memory is designed according to the PC4-21300 standard and features 4 GB of working space. It is compatible with 260-pin SO-DIMM DDR4 slots operating at 1.2 V. Users can achieve the manufacturer-specified effective frequency of 2666 MHz and CL19 timings.