The CT16G4SFD8266 Crucial DDR4-2666 SODIMM 16GB is a single module of DDR4 RAM designed for laptops and other devices that use SO-DIMM memory modules. With a total capacity of 16GB and a bus speed of PC4-21300 (DDR4-2666), this module offers fast and reliable performance for your computing needs. The Crucial brand ensures high quality and durability, backed by a lifetime manufacturer warranty, making it a dependable choice for upgrading your system's memory capacity.