Side gusseted bags are named for the gusset, or fold, on either side of the bag. The gussets expand when the package is filled with product, and larger sizes lay flat on their side and are good for palletizing. This package format has two long faces, or panels, on the front and the back for product branding. The side gusset bag protects your product from oxygen and moisture and the large sizes are typically used for pet food or agricultural products.