Thru-Hull Multibeam Transducer f/DDF3D. The 165T-B54 is a multi-beam transducer for the DFF3D that affords a 120 port-starboard view of the underwater world. Its compact design allows for easy installation. A built-in motion sensor stabilizes the display to give clear and stable images, even under rough sea conditions.WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.