Casio G shock GRAVITYMASTER Caps Auto EL Backlight 3Tee Auto EL Backlight China) Receives time calibration radio signals which keep the displayed time accurate Auto receive function (up to 6 times per day up to 5 times per day for China) Manual receive function Signal: US WWVB This unique technology combines Multi band 6 capability to receive any one of six time calibration signals around the globe with a receiver that acquires position and time information from GPS satellites GPW1000 – The World’s First GPS ATOMIC SOLAR HYBRID with CASIO original GPS Hybrid radio controlled technology built inside a TRIPLE G Shock Resistant structure