Orb of Binding

Orb of Binding is a currency item that can be used to upgrade a normal item to a rare item with up to four linked sockets. If used on an item with more than four sockets, those extra sockets will be lost.

It can be used on items without sockets, effectively functioning the same way as an Orb of Alchemy in this case. However, Orb of Binding cannot be used on Strongbox, while Orb of Alchemy can.

Note that player should not use this currency on 5L or 6L item, as this currency will unlink the item due to the currency "Upgrades [...] item with up to four linked sockets".

Item acquisition

Orb of Binding is a common drop which seems even more common than Orb of Alchemy (if excluding the factor of Alchemy Shard).

2 Orbs of Binding can be created by using 1 Craicic Shield Crab and 1 Craicic Sand Spitter are two other yellow beasts.