The Tite-Mark extensions come as 2 rods, one 3 inches long and one 6 inches long. They can also be joined together to make a 9 inch extension. The extensions are great if you need a little extra reach occasionally. Because there are no slots in the extensions, they should be used only when the fence can be used in the slotted rod that comes with the Tite-Mark. The extensions are designed for use with marking, reverse marking, and scoring blades.