T25P Poly Sure Opaque Poly Mailers measure 600mm x 700mm. Because they’re made from co-extruded recyclable and degradable 45 micron polythene, they can reduce mailing costs and your impact on the environment. The envelopes are water, puncture and tear resistant for extra protection, and are very likely to reduce returns due to damage of goods during transit. Their high opacity, heat sealed edges and tamper proof seal protect contents and keep them confidential.