TM185M Chirp-ready Transom MountAirmars TM185M is a transom mounted, Chirp ready transducer designed for offshore fishing and freshwater anglers spending their time in shallow to mid range depths. The medium frequency delivers the right combination of coverage under the boat, extended depth range, and the ability to produce clean and accurate target and structure returns in mid to deeper water. Medium frequency also provides excellent shallow to mid depth performance, bottom detail,