DESC: The Night Watch Collection's barometer features photo-luminescent dials and corrosion resistant, black epoxy coated aluminum case, offering information when you need it, day or night. Barometer/Thermometer/Hygrometer (BTH) combination instrument gives the user three essential elements in the weather equation - air pressure, air temperature and relative humidity. Each instrument is provided with complete instructions, mounting hardware, lifetime warranty, and a fresh battery as required. Dial: 3-1/2", Base: 4-1/2", Depth: 1-1/4". boating-equipment