I think i will just have to add the serial numbers in the comments field. The reason why i just don't write them in the invoice is that my technicians have a issue with losing the box or ripping the serial number by accident.

That could work, but then i would have to keep a list of the serial numbers. Possibly in the memo section of the part in inventory.

I could not find anything in a search. I have many parts with the same part #'s but have serial numbers as well that i need to keep track of in the customer's repair order. Only way i can find of doing it is separate parts but this makes checking sales a bit annoying. Any ideas?