Raymarine Bronze B744V D/S/T Thru-Hull Retractable Transducer (includes E66023 Fairing Block)Operating at both 50 kHz and 200 kHz, the B744V TRIDUCER Multisensor provides you with depth, speed, and temperature in one thru hull housing. This unit is ideal for all 600 Watt fishfinders and requires only a single hole in the hull. The B744Vs patented valve assembly prevents water from rushing into the hull when the insert is removed for cleaning or storage. The innovative housing design allows the TRIDUCER Multisensor to be fully recessed into