The product is a lot of 4 Samsung 16GB DDR4 SDRAM memory modules with a total capacity of 64GB. Each module has a capacity of 16GB, a bus speed of PC4-21300 (DDR4-2666), and a form factor of SO-DIMM. This RAM is designed for laptops and is a reliable and high-quality option for upgrading or replacing existing memory modules. The brand Samsung ensures a reputation for excellence in memory products, making this a dependable choice for improving the performance of your computer.