All Printful Products.
This collection is only used to set the shipping rules for Automated Shipping Rules app. Any product in this collection will receive the calculated rates from Printful. You may need to continuously add products to this collection and also sync the product templates in the shipping app to make the shipping rates work. You originally set this up because if Printful products are not in a separate shipping profile, then customers will be able to select non-printful calculated shipping rates and you will likely lose money and/or the shipping method will not be transferred to the Printful order.