165T-SS54 Stainless Steel Thru-Hull Transducer for DFF3D Sounder. Stainless Thru-Hull Multi-Beam Transducer The 165T-SS54 is a multi-beam transducer for the DFF3D that affords a 120 degree port-starboard view of the underwater world. A built-in motion sensor stabilizes the display to give clear and stable images.Features: Stainless Steel Thru Hull with high speed fairing block. Can be flush mounted in keel without using fairing block. DFF3D operating frequency: 165 kHz. 2 x 10M Cables: Bare ended cable for DFF3D sonar and 7-pin connector for the motion sensor. Compact design. Built-in motion sensor. Built-in temp sensor.