Explanation: A Search and Rescue Transponder (SART) is designed to aid in locating distress situations. Once activated (manually or by water), it enters a standby mode, conserving power. The SART functions as a transponder, meaning it *responds* to an external signal. It begins a transmission only when interrogated by a searching vessel's or aircraft's X-band radar. Upon receiving a radar pulse, the SART transmits a unique sequence of 12 dots that appear on the interrogating radar screen, indicating its location. It does not radiate continuously after activation, nor is it keyed by an operator. This "listen-and-respond" mechanism ensures efficient battery use and targeted detection.