Backpack
From Eco - English Wiki
A Backpack provides extra storage space for a player. Every player has a backpack equipped when they first log in to a server. At a Tailoring Table a Player can craft Backpacks to increase their carrying weight, movement speed, or decrease calories consumed. The GUI for the backpack can be toggled by pressing B
.
Any kind of item that can be stored in your toolbar can also be stored in your backpack (up to 16 item stacks).
All blocks cannot be stored in a backpack. They need to be carried by hand, or by using a vehicle such as a cart.