The ALT1-Z was designed with aviators and world travellers in mind. Z stands for ‘Zulu Time’ and allows the wearer to display local time together with the official world time standard: Universal Time Coordinated (UTC), Greenwich Mean Time (GMT), or even Zulu time (Z). UTC replaced GMT in 1972 as the international reference standard for communications, military, aviation, maritime and other activities that span multiple time zones. It boasts a cleaner dial and the 24hr function has been moved to the bezel for greater clarity. Greater detailing around the stepped sub dials with micro lines has been made to give the dial more depth. Black leather strap with solid deployment buckle and engraved security clasp.