552 Subfield $j - Attribute units of measurement and resolution:

Subfield $j contains the standard of measurement for an attribute value and the smallest unit increment to which an attribute value is measured.

Example:

552 ##$afloodplain polygon$b100 and 500 year floodplain zones (FIRM maps (FEMA))$cuser-id$dfloodplain zone, USACERL$g100-500$jYears (time)