By default, the AMPM property is "AM PM". Use the AMPM property to change the AM/PM indicators when the control displays time, and the %a field is included in the FormatUserDate property. If the AMPM property is empty string, and the %a field is present, the hours will still be displayed in the AM/PM format, but the AM/PM indicators will not be displayed. if the %a field is not present, the hours get displayed in 24 hours format. The [Calendar.]LocAMPM property specifies specifies the AM and PM indicators, as indicated in the regional settings.