Echotest Depth Sounder - A small, handheld depth sounder, which is extremely simple to operate and popular with dinghy sailors and scuba divers. It is totally waterproof and gives readings to a maximum depth of 80 metres. Has a Large LCD Display with LED back light, making it ideal for use at night when you are making your way up the creek to the local hostelry. As the sounder will not read through air, you simply put the head of the depth sounder into the water or against the hull of the boat to see how much water is beneath you. Runs off one 9V drycell battery. Size: L198 x Dia. 42mm.