An organization named the National Motor Freight Traffic Association (NMFTA) publishes a list of freight class designations, codes, and subclasses for frequently shipped commodities (https://classit.nmfta.org/). You must pay a subscription fee to view it. Find more information about freight classes from the experts at Koho for free on our freight classes pages.
Freight Class 500 freight is the most expensive to ship. This classification is reserved for items of very high value or for items that use lots of space but weigh very little.
NOI stands for Not Otherwise Indicated. This is used when a commodity does not have an NMFC code. In these cases, density is usually used to determine freight class.