Subclasses for
The National Motor Freight Classification (NMFC) is the freight classification system devised by the National Motor Freight Traffic Association (NMFTA) and is used for all interstate, intrastate, and foreign commercial movement of LTL cargo. NMFC codes provide standardized freight classes to determine the ease of transport of many of the wide variety of commodities that are shipped together in LTL shipments.
Freight class 50 is the least expensive because it refers to the freight that is easiest to transport for the carriers.
If you don't include an NMFC code on your BOL, it is very likely that your carrier will charge you a reclassification fee and charge you the cost of shipping the freight they they determine your shipment is.