Standard behaviour in Business Central allows for 'Customer', 'Vendor' and 'Bar Code' Item references to have duplications, i..e a Customer can use the same Item reference across more than 1 Item. 

However, we understand that as a business, this may not be viable and you may want to prohibit using duplicated references for items, making them more unique. 

Due to this, one of the features within Clever Trade Plus is the ability to prevent Items from having an Item Reference that exists for another Item. 

More information on this can be found on the Setup article next.