The product is a lot of 2 Micron 4GB 1Rx16 PC4-2666v-UC0-11 UDIMM desktop RAM modules. Each module has a capacity of 4GB and is designed for DDR4 SDRAM memory type. The modules have ECC memory features and come with a lifetime manufacturer warranty. They have a form factor of UDIMM and are DDR4-2666V bus speed. Made in the United States, these modules are reliable and high-quality for upgrading your computer's memory capacity.