Backpacks are equipment items used to store blocks, including ores. They are purchased at the shops in every zone.
Backpack Characteristics
Storage
Storage is the sole attribute of backpacks, and indicates how many blocks the backpack is able to carry before the contents must be sold for Coins to empty it. The only exception to this rule is the Quantum Backpack, which allows players to decide when they want to sell their contents rather than being forced to after amassing a certain amount.
Backpacks, like Tools, have the ability to have a skin applied to them. Most only effect the backpack cosmetically, but Mythical skins provide buffs to mining.
Each Rebirth after the first will increase all Backpacks coin prices by 50% - ones bought with Rebirth Tokens or Robux aren't effected by either.
Rebirth Shop
Unlike other backpacks, these are purchased with Rebirth Tokens instead of Coins and the shop itself can be accessed at any vendor. Rebirth Shop backpacks are permanently unlocked once purchased, not lost after the user Rebirths.