• A Product Bundle is a Shopify Product that is made of a combination of other Shopify Products
• An example is: A bed is made of a mattress (x1) and pillows (x2). If you sell a bed, but also mattresses and pillows individually, then a bed is a good candidate for a Product Bundle
• The inventory of the bundle (the bed in this example) will be based on the Shopify inventory of the components (mattress and pillow in this example)
• So if the component products (Mattress and Pillow) are using Raw Materials, you need to turn on 'Update Shopify Inventory' so that their Shopify Inventory is accurate (and in turn the bundle's (Bed) inventory is accurate)