The BYTECC BTU3-EC200 is a brand of a USB 3.0 to SATA III external hard drive enclosure. It is used to convert a 2.5-inch SATA III hard drive or solid-state drive into an external drive that can be connected to a computer through a USB 3.0 port. The enclosure provides a convenient way to access data stored on a SATA III drive and transfer it to a computer. The BTU3-EC200 model supports USB 3.0 speeds, allowing for fast data transfer rates, and is also compatible with USB 2.0 and USB 1.1 ports. The enclosure has a compact and lightweight design, making it easy to carry around, and is equipped with a built-in fan to keep the drive cool during operation.