Anchoring security for cruising sailors! Find deep water easily from your dinghy. This unique pocket-sized depth sounder is very accurate and of very high quality. It is useful for boating, fishing, scuba diving, coastal survey, and scientific work.  Features  Reads in Feet or Meters, to the nearest tenth through a solid hull, inflatable bottom,  water, or ice. This is an extremely accurate unit when used properly.  200 kHz with 24º beam angle  Range from 2 feet to 260 feet  Each reading is backlit and stays displayed for ten seconds. Simply put the head in  the water, or against the solid hull of a boat. (Sonar will not read through air.) Specifications FREQUENCY: 200kz (Beam Angle 24º)WATERPROOF: to 160 feet; 50 metersRANGE: 2-260 feet or .6 - 79 metersPOWER: Standard 9V dry cell battery (good for 500 10 second readings)MEASURES: 7.7 x 1.7 inches (198x42mm)WEIGHS: 10 oz / 300 grams