Bird S Pole 30 Extension is for 1 in. diameter S Poles only. The actual extension is 30.5 in. but it is 34 in. overall size with one tapered end to insert into an existing 1 in. diameter S pole within this category. Slots and pins are on both sides and are used to secure the joints together. Extension comes with a protective rubber cap as shown. A good way to give some extra height or if you need to replace pole sections.