C3 Metallic Red Padded Bubble Envelopes (Qty 50) 320mm x 450mm1 2 day delivery as standard on this product C3 Metallic Red Padded Bubble Envelopes. Box of 50 metallic red padded bubble mailers. These red padded envelopes measure 320mm x 450mm internal measurement. This our our largest envelope from this range and is designed to fit an A3 document or brochure. These bubble mailers feature a peel and seal closure. Measurements displayed are all internal. All of our bubble bags are made with 40% recycled materials