There are many different types of watch functions. The most common are analog, chronograph and tachymeter.
Analog – The most simplest type which everyone is probably familiar with. Sometimes has a second hand.
Chronograph – This function was specifically designed to incorporate a stopwatch into a normal without losing any functionality.
Tachymeter – A scale is used for this function, which can be used to calculate length of space based on the rate at which something moves or speed based on time taken to travel.
Water Resistance – This is a feature which makes the watch resistant in water. Read specific watch water resistance information carefully.