The Crucial Ballistix 16GB (4 x 8GB) PC4-25600 (DDR4-2666) Memory kit includes four DIMM modules with a total capacity of 24GB. Each module has a capacity of 8GB, and they are designed for high performance with DDR4 DRAM technology. The memory kit features ECC memory for error correction, a lifetime manufacturer warranty, and a bus speed of PC4-21300 (DDR4-2666). With its compact dimensions of 5.2 inches in length, 1.5 inches in height, and 0.2 inches in width, this memory kit is a reliable choice for enhancing the performance of your computer system.