The WD Blue 4TB Hard Drive WD40EZAZ is a high-performance internal desktop drive designed for use in laptops and PCs. With a rotation speed of 5400 RPM and a cache size of 64 MB, this SATA III drive offers fast read speeds of up to 180MB/s. The drive is equipped with features such as low noise level and ROHS compliance, making it a reliable storage solution for various computing needs. With its 3.5-inch form factor and WD Blue product line from Western Digital, this hard drive is a dependable choice for expanding storage capacity in your system.