Optimum Time OS 545 Hand held Compass and Sailing Watch - Large 90mm x 63mm overall ABS case, Massive 17mm upper digit height and 9mm lower digit height. Lanyard, karabiner, and clipboard mount options, Water Resistant to 3 atm Plus Shock Resistant Construction. Dot matrix panel to aid function selection, Normal Timekeeping Mode, Calendar, and Alarm . Specialist Sailing Timer Functions:Countdown repeat option or Countdown and Up to show elapsed time for handicap races 5,4,1,0 ISAF start sequence pre-programmed with audible warning signals 5 minute, 3 minute and 1 minute programs as well “Sync Button” for instant synchronisation if a gun is missed. Electronic Compass with Indication of position of North, plus 3 digit bearing reading to within one degree Cardinal Bearing shown on dot matrix panel (eg NNW) Declination (Variation) Angle adjustment for worldwide use. Electro-luminescence backlight feature