SEEKER (VADR) Acoustic Directional Receiver 4.5” x 10.2” Quickly and easily Navigate and Relocate your vehicle with the RJE SEEKER. The acoustic receiver mounts on a ROV or AUV, for tracking acoustic beacons between 25kHz - 40kHz at full ocean depth. The SEEKER is compatible with ATT400 Series Acoustic Transponders, and can also function as a acoustic transponder interrogator, providing greater flexibility for your subsea needs.