天行GMT: 全球自定义 is a convenient time syncing app that allows iPhone users to synchronize their atomic radio clocks with their smartphone. Developed by Beijing Zhongfang Internet Technology Co. Ltd., this app is licensed as a full version and is available for iOSand above.

Using this app is easy, simply place the headphone speaker next to the atomic radio clock's internal antenna or place the clock's internal radio antenna as close to the smartphone speaker as possible. Keep the volume as high as possible before starting to distort. When the time sync receive mode is active, the clocks will sync within 2 to 3 minutes.

With this app, users can conveniently sync their atomic radio clocks and ensure accurate timekeeping. Overall, 天行GMT: 全球自定义 is a useful utility app that is worth trying out.