19) Prefer the 24-hour system to the 12-hour system. Include both the hours and the minutes (not the seconds). In cross-border contracts, add the ISO time-zone indicator.
When writing times, prefer using a colon over a full stop between hours and minutes. Do not add hrs or o’clock: 11:30 h CET.
It is important to note that a reference to 12:00 p.m. is ambiguous. In view of the risk that a party may rely on an erroneous combination of a.m. used in the 24-hour system, it is strongly recommended that a contract clause either refer to 11:59 a.m. or 00:01 p.m. as a marking point in time.