Some property values take a time duration. Durations are expressed as numbers followed by units. For example 1 s means one second, and 2 w means two weeks. Some durations have minimum granularity or maximum units, so you cannot necessary specify every duration in milliseconds or weeks for example. Some durations allow you to use a special value to mean unlimited. Units are specified as follows. ms: milliseconds s: seconds m: minutes h: hours d: days w: weeks