(20) 4×8″ Standard Size Premium Designer Bubble Shipping Mailers (Seamlessly Printed With No Ugly Logos! Make Customers Remember YOUR Brand) Secure Adhesive Seal, For Simple Pull and Seal Prepare a Bubble Padded, Unique, Secure, and Cost Saving Shipment Size Selection: To accurately determine the size of your product, take into consideration its thickness. When measuring width, add the product’s width, thickness, and ½ inch. For length, add the product’s length, thickness, and 1 inch. Remember, the thickness of your product is a key factor in determining size of bag you need.