Backpack
Formula Vault Backpack
Level 552+ to equip- 47 backpack slots
Secret Formula: recharges 60 s faster
Only for whoever has this ability in the talent tree
RaritiesCommonNo extra stats4,040 
Uncommon1 extra stat · up to +26,060
Rare2 extra stats · up to +410,100
Epic3 extra stats · up to +616,160
Legendary4 extra stats · up to +828,280
Mythic5 extra stats · up to +1048,480
Regular monsters drop equipment up to Epic, the hunt boss up to Legendary. Mythic only comes from the daily boss.
Where it dropsA safe on the back, combination unknown. The secret formula is ready sooner.