Fully automatic and highly accurate, the BALL Manufacture GMT Caliber RRM7337-C is an officially certified chronometer. With true GMT status, its quick-set functionality changes the local 12-hour hand by using the crown. The GMT hand is completely unaffected while the seconds hand continues to move – for an uninterrupted precision. As the 12-hour hand jumps in one-hour increments, the date wheel moves in perfect synchronization and always indicates the correct date of the local time zone. The movement and all its smart functionality are shielded by 1,000 Gauss anti-magnetic protective technology. All four models are powered by COSC certified movements, protected by our patented Amortiser® anti-shock system and enhanced by cold temperature resistance oil to ensure ultimate timekeeping in sub-zero temperatures.