Strong but smart, these best value heavy duty mailing sacks offer a durable yet economical solution to your mailing needs. Made from co-extruded (2 material) polythene, these mailing sacks look great with a white outer layer and black inner layer, but don’t be fooled by their smart appearance – these 50 micron (200 gauge) heavy duty mailers are tough and durable too. You can add a postal address with a label or simply write on the bag with a pen.