Anamet - CE Code Heavy Duty Liquid-tight conduit and marking
John Richardson
October 26, 2020 – The 2018 version of CE Code-Part II introduced a new product rating (and related marking) for liquidtight conduits—Heavy Duty (HD)—which is now required for use in any hazardous location that allows the use of liquidtight flexible metal conduit.
(source: Electrical Business Magazine)
https://www.ebmag.com/ce-code-heavy-duty-liquidtight-conduit-and-marking/