A Pack of 40, Size 0 PostPak Bubble Envelopes from the Post Office. These tough, durable bubble bags are made with a high quality white paper exterior containing a protective lightweight bubble lining ensuring its contents are transported in comfort and without the risk of damage. PostPak bubble envelopes will make sure your post stays safely enclosed and protected. Great for sending A4 sized photographs, documents or anything that can flex without breaking such as books, catalogues and leaflets. The bubble envelopes by PostPak are a great choice for cost saving, minimizing postage rates. These bubble envelopes come with an easy to write on surface so no need for postage labels.