Earlier in this thread a couple of people asked about standards in pound-test ratings, and there aren't any. You can put large-diameter line that breaks at over 20 pounds on a spool, call it 10-pound line and sell it that way. In fact, that's pretty much what some of the line manufacturers do. The industry doesn't regulate it; it's whatever the fishing public will accept. Somewhere on the spool you should be able to find the diameter, usually stated in thousanths of an inch, and if you examine several different lines in the same test, you'll likely notice a wide variation in diameters. That "10-pound" mono that really breaks at 20+ will be the thicker stuff!