Citizen Promaster Air in silver-tone stainless steel case with a green ion-plated rotating bezel with a professional calculator function and tachymeter on a green dial with luminous hands and markers and a sapphire crystal. Atomic time clock synchronization for superior accuracy, a 1-second chronograph that measures up to 60 min, and a perpetual calendar. Silver-tone stainless steel bracelet fastens with a safety fold over clasp with push buttons. Water resistant to 200M. Powered by Eco-Drive so it will charge by any light and never needs a battery