Raymarine's RV-300 Plastic All-In-One Through Hull Transducer is  designed for inboard and outboard powerboats. The RV-300 lets you easily  identify structures and locate fish with the life-like clarity of  RealVision 3D™ sonar.
 The RV-300 is a 4-channel, Wide Spectrum CHIRP transducer with  DownVision™, SideVision™, high frequency CHIRP fish targeting and  RealVision 3D™ sonar inside. The transducer also has a built-in attitude  and heading reference system (AHRS) that stabilizes the sonar imagery,  compensating automatically for vessel motion. You'll enjoy crystal-clear  imagery even in waves, swells, and when maneuvering. The RV-300 also  has a built-in fast response water temperature sensor for quick,  accurate readings.
 The RV-300 features a rugged plastic through hull body suitable for  fiberglass, steel or aluminum hulls. The RealVision 3D™ transducer  elements are arranged with a 0° offset for boats with flat bottoms. The  low-profile design slips effortlessly through the water without causing  drag or cavitation. The near-flush RV-300 works great on trailered boats  too and with no fairing block to cut, installation is a breeze.