POE Orb of Fusing is a currency item that can be used to re-roll the links between sockets on an item. It can also be used to change the number of sockets on an item. The Orb of Fusing can be obtained by selling linked items to any vendor, or by killing monsters, opening chests, and completing quests in the game.

To use the Orb of Fusing, right-click the item with the sockets you want to change, and then left-click the Orb of Fusing in your inventory. This will give you the option to re-roll the links between the sockets, or to add or remove sockets. Depending on the item, the cost of using an Orb of Fusing will vary.

Players can also spend Orb of Fusing on other items. If a player has a piece of equipment with several linked sockets and wants to re-roll them, they can use an Orb of Fusing to do so. Players can also use Orb of Fusing to craft items, such as rare items and uniques. Additionally, players can use Orb of Fusing to upgrade a rare item to a higher level of rarity.

Overall, the Orb of Fusing is a valuable currency item in Path of Exile that can be used to re-roll the links between sockets on an item, or to change the number of sockets on an item. It can also be used to craft items, upgrade items, and more.