Serial Attached SCSI (SAS) controllers are hardware components that manage data transfer between a computer's central processing unit and storage devices like hard drives and solid-state drives. They use a point-to-point architecture, allowing for faster data transfer rates and improved performance compared to older technologies like Parallel SCSI. SAS controllers support multiple devices through a single connection, enabling the use of SAS and SATA drives. They are commonly used in enterprise environments where reliability and speed are crucial, making them ideal for servers and data centers that require efficient data management and storage solutions.