Designed for professional use that will let you reach your limits. Strengthen your watch collection with the latest Promaster Sky. It is resilient to the rigors of everyday wear. Crafted with a light brown calf strap, sleek blue dial with yellow accents, sapphire glass, and a 44.4 mm case. For enhanced performance, features include perpetual calendar, radio controlled, world time in 26 cities, aviation slide rule inner ring and a cockpit dial design. Powered by Eco-Drive technology, never needs a battery, only a light source.