Catalogs are designed for using, not confusing, but it is not unusual for catalog users to make mistakes in tracking down part numbers. Simple goofs are the most common and costly. For instance, often the user will find the correct listing, but then he or she reads across the wrong line. On the other hand, sometimes everything is done correctly, but a mistake is made in copying or trying to remember the part number. Alternatively, you can be mixed up in using a cross-reference, or working with an outdated catalog, or overlooking a footnote. Such mistakes happen every day to even the most experienced. All you can do is try your best to avoid them.