Staples are classified using two sets of numbers. The first set represents the thickness or gauge of the staple wire (the smaller the number, the thicker the wire). "24" and "23" classify these staples as 24 gauge and 23 gauge standard office staples are typically 26 gauge and not as durable.

The second set of numbers represent the length (in millimeters) of the staple legs. To help determine the length of staple that is needed for your application, add the number of sheets being stapled (10 sheets of standard paper is approximately 1mm) and add 3mm for clinching.