Smartphone Link/App Connectivity Features. Smartphone Link feature. CASIO WATCHES. Resin Band. Easy watch setting. battery life: 2 years on CR2016. Double LED light LED light for the face (Auto LED light, Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds), afterglow) LED backlight for the digital display (Auto LED light, Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds), afterglow).