IPE posts
IPE posts are a special kind of I beam post that is used for palisade fencing in England, South Africa and other countries.
These posts are lighter weight than typical structural I beams, and are usually 100 x 55mm, or about 4 x 2 inches. Even though they are lighter than structural I beams, these posts are significantly stronger than most tubular posts, which makes them ideal for high security fence systems.
When IPE posts are used for palisade fence, they usually have slotted holes in the weft of the post, which are used to attach panels using fishplates.