If you are pre-registering samples not in OAL bottles (i.e. with no K number on the bottle) you need to generate a K number and print it. In pre-registration you should NEVER press print labels (please emphasise this point to the user) and always press the send to lab button if using one of our bottles. Ideally, if using your own container you should press send to lab, then go to samples in transit and print any labels off from there. The full guide for pre-registering samples not in an OAL bottle is here https://learnoilanalysis.com/faq/pre-registering-samples-not-in-oil-analysis-lab-lubewear-bottles/ , read the article and scroll to the bottom for the k number generator link, however you should not need this in almost all cases and should order one of our pre-paid bottles that all come with a k number on.