Larzuk's Puzzlebox
Larzuk's Puzzlebox is a PD2 item that can add 1-2 sockets with equal chances to an item if that item is capable of gaining sockets. Its droprate is similar to a high rune, it is therefore pretty uncommon and of value.
Larzuks Puzzlebox is used to add sockets to end-game items after using a Worldstone Shard resulting in a desired corruption.
Caution: Throwing weapons cannot gain sockets, but the puzzlebox will still be consumed if used on one.