Images:

gw2-godskull-effigy-focus-1gw2-godskull-effigy-focus-2gw2-godskull-effigy-focus-3

Set:

Slot Item Name Trading Post Preview Code
Focus http://db.dulfy.net/item/46044 GW2 TP [&AgE5NwAA]

Where to Obtain:

Artificer: 1 Hard Focus Casing + 1 Hard Focus Core + 3 Large Skull
Recipe purchased from Tarstar Chief in Fireheart Rise