The shelf time on Berkley line. All spools of Berkley have a date on them when they were made. If u look on the spool itself down under the bar code u will see a letter a dash a number a dash a number a dash a number that is the date such as: F-03-5-21. F = the month (F being June) 03 is the day and 5 is the year 21 is the machine it was made on. So F-03-5-21 was made June 03 2005. I hope this helps anyone buying line. I bought a bad spool at a store(which I am not going to mention), I called Berkley and that was the first thing i was asked for was that set of numbers and was told what they represent. Just so happened that spool of line was 2 years old. I sent a piece of line and the label from the spool with receipt to Berkley and they sent me a new spool of line. Luckily it was a practice day and not tourney day when i used it.

Dennis