Amazon.comThe Humminbird XHS 9 HDSI 180 T Transom Mount Transducer is a high-speed transducer designed to mount on the transom, or back, of the boat, in contact with the surface of the water, and operate in conjunction with a compatible Humminbird sonar or fish finder system. This unit is combination DualBeam PLUS transducer that features 20- and 60-degree cone angles operating on 200 kHz and 83 kHx frequencies respectively, as well as a side-imaging sonar with two 84-degree beams operating at 800 kHz.The XHS 9 HDSI 180 T includes a built-in temperature sensor, a 20-foot cable, and all the necessary high-speed hardware to get up and running right away. Although this unit has the same hole pattern as some older-version transducers, it utilizes a new design that is more secure and less prone to kick up at the high force of waves, as well as having an improved running angle, and an optional lock-down screw to override the kick up. The Humminbird XHS 9 HDSI 180 T transducer is specifically designed for use with Humminbird's 997c SI Combo fish finder and other side-imaging sonar systems. This transducer is backed by Humminbird's one-year limited warranty.Product DescriptionTransom Mount, Dual/High Definition Side Imaging 20/60/180 Degree, 200/83/455/800 kHz with built-in temperature.