The Western Digital My Book 4TB external hard drive is a desktop external HDD with a 3.5-inch form factor, designed for compatibility with PCs. It features a USB 3.0 specification for fast data transfer, with a storage capacity of 4TB. The sleek black color and compact design make it a versatile and convenient option for expanding storage capacity on your computer. With the trusted brand of Western Digital and the reliable HDD drive type, this external hard drive is a reliable choice for your storage needs.