The Adaptec AVA-1505/1515 AT to SCSI Host Adapter is a specialized interface card that allows a computer to communicate with a SCSI device. As a Host Adapter, it provides a way for the computer to connect and access the SCSI peripherals such as hard drives, scanners, and other storage devices. With the included cable, this Adaptec adapter offers a reliable and efficient way to integrate SCSI technology into a computer system, making it a valuable component for those looking to expand their storage capabilities.