Aviditi Poly Mailers. Strong polyolefin mailers protect products from moisture during shipping. Mailers are puncture and tear resistant. High strength seams will keep contents intact even if over packed. The outer surface of the mailer is white and the inner lining is silver. Constructed from 2.5 Mil polyethylene with a self-seal closure on one. Measures 15-1/2-inches length by 12-inches width.