Your inventory is organized in Green Bits by Product Types, Products, and Inventory Items. Every item in your store will have associated Inventory, Product, and Product Type in Green Bits.
Product Types > Products > Inventory Items
For example, let's say your store sells concentrate cartridges (Product Type). You sell several different strains from different vendors (Products). You will receive specific quantities of Products in multiple packages over time (Inventory Items).
Learn more about Product Types, Products, and Inventory Items and how they relate to each other: