A calendar function can either have just the day number, can show the day, date and month, or may be a perpetual calendar, which takes into account the varying number of days in a month and leap years.

A dial that tells the time in different time zones around the world. The dial is usually found on the outer edge of the watch face.

A watch that can perform different functions, such as a stopwatch or a countdown time, whilst still giving the correct time.

A function that illuminates your watch during the night or at the press of a button. Some watches have a special light absorbing paint on the hour and minute hands so they can be seen in the dark. Others are illuminated by pressing a button on the case.

The ability of a watch to withstand water to various pressures. The term is followed by a number and metres, indicating the depth of water your watch can withstand, e.g. Water resistant 50m. This is only a guide as watches are usually tested in a laboratory and not in the sea.

Non-water resistant watches provide minimal moisture protection. They can withstand the occasional rain shower but should not be immersed in water at any time.