Our metallic silver bubble envelopes measuring 320 x 450mm internally and 330 x 455mm externally are the largest size in our Metallic Silver range. Made from laminated aluminium to offer tear, puncture, and water resistance and excellent robust protection for a wide range of items, these metallic bubble envelopes have a peel and seal adhesive strip to give a secure tamper-proof seal. Our eye-catching padded envelopes offer a low-cost solution for increasing direct mail response rates thanks to their distinctive glossy outer and have 50 bags per box.