Clocks and watches with a 24-hour analog dial have an hour hand that makes one complete revolution, 360°, in a day (24 hours per revolution). The more familiar 12-hour analog dial has an hour hand that makes two complete revolutions in a day (12 hours per revolution). Modern 24-hour analog dials—other than sundials—are almost always marked with 24 numbers or hour marks around the edge, using the 24-hour clock system. These dials do not need to indicate AM or PM.