The product is a lot of 4 Western Digital WD Blue WD10EZEX 1TB 3.5-inch SATA III 7200RPM 64MB HDD internal desktop drives. These hard drives are designed for high performance with a rotation speed of 7200 RPM and a cache size of 64MB. They have a storage capacity of 1TB and are compatible with PCs. The drives are in a 3.5-inch form factor and feature S.M.A.R.T. technology for added reliability. With a read speed of 600 MB/s and a transfer rate of 6 Gbps, these Western Digital WD Blue drives offer fast data access and storage capabilities.