The endurance II 135 radio room quartz clock w/ military time measures 5"(Dial) x 7"(Base) x 2 1/2"(Depth) and weighs 2 lbs. Light, strong and durable, the Endurance II 24 Hour Radio Room Quartz Clock combines two clocks in one instrument. This innovative clock incorporates the dial of a radio room clock with a 24-hour clock movement. Radio Room Clocks were introduced in the early 1900s, in part, as a result of the tragic sinking of the Titanic. The Titanic had difficulty contacting nearby ships for rescue help because the distress call system was ineffective. The Endurance II 24 Hour Radio Room Clock displays two 3-minute fan lines in red and two in green. These colored markings represent designated silence periods when only emergency radio messages were to be transmitted and received. The 24 hour clock display divides the day into 24 hour increments, indicating the hours from 0(midnight) to 23. This method of time-keeping is often referred to as military time. The Endurance II 24 Hour Radio Room Quartz Clock in brass finish features a traditional front opening porthole case housing an accurate quartz movement. Constructed of the same high luster, maintenance-free, ultra-hard finish that is a hallmark of the original Endurance collection, this unique clock is weather resistant and guaranteed to never tarnish. Beveled glass crystal. Mounting methods for boat or shore. AA battery included. Lifetime warranty on finish and movement.