Bronze Thru Hull TransducerBronze Thru-Hull Transducers are for large boats and for boats with in-board motors that make typical Transom Mount Transducers ineffective. They are not recommended for trailered boats as the transducer is not flush with the hull. Bronze Thru-Hull Transducers require that a hole be drilled in the hull and the shaping of a fairing block. Professional installation is recommended. Plastic Thru-Hull Transducers are an alternative to Bronze Thru-Hull Transducers.Description: Bronze thru hull transducer, single or dual beam use. 20/60 degree, 200/83kHz. Transducer dimensions: 5.25L X 2.75W X 1.2D (below hull); Shaft diameter: .86. Fairing block not included.WARNING: This product can expose you to chemicals including LEAD which is known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.