A bundled product is an Inventory Integration feature that allows you to assign a single SKU to multiple products. This is useful if you sell multiple products as a pack or a group. Unlike merged products, when you bundle products you can remove additional items from the bundle. You can also turn off the bundle option for the specific SKU.
A merchant who sells socks may offer three packs in different colors. Each of the individual sock colors has a unique SKU - sock_blue, sock_red, sock_black. When bundled using the bundled product feature, these three SKUs can be associated with a parent SKU - sock_3s.
Once products are bundled, stock levels can be adjusted for all associated SKUs. When a merchant sells a pack of any of the three SKUs associated with "sock_3" SKU, each of the individual SKU stock levels will be adjusted as well.