Backpack

Backpacks are unlocked in the Leather collection, and can be interacted with to open and store items. It can be opened by going to Storage in your SkyBlock Menu and right clicking one of the backpacks you have stored.

Due to the Backpack revamp, all legacy backpacks have been made obsolete. If you had any items stored in your legacy backpack, you can right click it to store it in the Storage menu.

Crafting
There are 5 sizes of the backpack:

Dyeing
Backpacks can be colored with 8 of any color Dye. (Backpack in middle surrounded by a single color of Dye)

Example (using Gray Dye):

An overview of all colored backpacks:

Trivia

 * A backpack cannot be placed in another backpack, nor sold to an NPC.
 * Backpacks are notorious items used in Scams by hiding junk items inside and trading them away as something else. A hidden update on May 27, 2020 revealed that item names were stored inside a backpack, making backpack scams less effective; this change has since been reverted.
 * Backpacks are known for being problematic and often used for duping across skyblock's history. This caused them to be disabled several times. The longest they've ever been disabled is from April 5, 2021 to April 20, 2021. Although they were enabled for a very short time on April 8 but it was overnight so most people weren't able to get items out in time so most people were locked out of backpacks for a whopping 15 days. This caused them to rework backpacks and only have them be accessible when putting them in the storage menu where you can also access your ender chests.