Import Reference Number

From UG

An import reference number is a unique, consecutive number assigned by an import operator at the time they arrange for the import customs clearance for a CT record and will always include a 2 letter code to define the MOT.

There are 3 types of MOT's that can be applied for import shipments, Air Ocean & Trucking and each have a unique two letter code to identify them:

AI = air imports SI = sea (aka ocean) imports TR = any type of trucking imports