"Raymarine ST300/P371 Through Hull Speed Sensor Brand New Includes Two Year Warranty, The Raymarine E26008 is a plastic through hull speed sensor for ST40 instruments
This is compatible with hull material aluminum and fiberglass surfaces and P371 plastic low profile through speed tranducer. It operates on frequency of 200 kHZ and also includes 30 feet cable. E26008 Features: Through Hull Speed Sensor, Part Number: E26008, Frequency 200 kHz, Suitable w/ Aluminum & Fiberglass, Speed & Temperature, 2"" Hole Diameter, Includes 30 Ft Cable, For Raymarine Models: ST40 Instruments"