These Tough Solar models provide a choice of either the original G-5600 G-SHOCK design or the G-6900 design that is so popular among followers of today's street fashions. The Tough Solar system, which is equipped without changing the basic design of the watches, makes it possible to generate enough power to keep the watch running with minimal exposure to normal lighting. The simple designs of these watches were achieved by eliminating as much coloring and decoration as possible. The result is two models that capture the essence of the basic G-SHOCK.