It starts with a simple, yet revolutionary concept: a watch that never needs a battery. Citizen Eco-Drive technology harnesses the power of light - from any natural or artificial light source - and converts it into energy which is stored in an Eco-Drive energy cell. It recharges continuously in any kind of light to run forever. The Citizen GMT model a stylish and sturdy watch for the outdoor traveller. It has a reinforced nylon strap sapphire glass for extra resillience. Plus it never needs batteries so won`t let you down when you need it.