Casio G-Shock GW6900 In-Depth Review

The GW6900 is based on the classic design of the DW6900 which was first available in 1995. Both the DW6900 and the GW6900 are still available new in many color varieties. I prefer the newer GW6900 because it has Casio's "Tough Solar" power source and Multiband 6. Tough Solar means that there's a solar cell in the face of the watch to keep the battery (or capacitor) continually charged. Multiband 6 means the watch has a built-in radio receiver to keep the watch accurate. If the watch is used in areas where atomic time reception is available (from 6 major transmitters in different parts of the northern hemisphere) then it can update its time automatically every night. You could potentially wear this watch for many, many years without having to change a battery nor adjust the time (unless you go to a different time zone).
The GW6900 watch featured in this video uses Casio's Module 3179. Detailed instructions are available for download from Casio's website. (The non-solar, non-Multiband 6 version uses module 3230.)