Tough Solar. A Tough Solar power system generates enough energy to ensure uninterrupted operation of power-hungry functions. Smartphone app for use with G-SHOCK Smartphone Link models. Super Illuminator with Full Auto light (2-seconds/4-seconds duration switching, fade in/fade out). G Shock Watches, Cool Watches, Watches For Men, Casio G-shock, Casio Watch, Internet Time, Protrek, Bluetooth Watch, Solar Watch