Maritime Radio Silence Clock/Radio Room Clock Quartz Clock With Radio Silence Zone MODEL:GL198-C5 Material:Brass Base: 7"(180MM) Dial: 5"(124MM) Depth:1-3/4"(45MM) FEATURE: Waterproof / Tarnishproof For use in radio rooms. The diameter of the dial is 180 mm with the numerals 1 - 12 on the outer edge and the numerals 13 - 00 on the inner side showing international time. Seconds are marked clearly in red between the hour numerals. There are two 3 minute silent periods at 15 and 45 minutes past the hour marked in red for emergency signals, and two 3 minute silent periods at 0 and 30 minutes in green for distress signals. The clock has 2 hour hands, one to be set in Greenwich Mean Time and the other to indicate local time.
