Size 352 (MJ352) MailJacket™ cardboard capacity mailers are ideal for mailing books and flat packages and boxes. They’re completely unbranded and come in boxes of 100. Using MailJacket™ will ensure more of the products you send qualify for reduced-cost delivery options, such as Royal Mail’s large letter, lowering your company’s overall postal costs. The 400 gsm 100% recycled solid board envelopes include pre-creased capacity grooves that allow them to expand, This means they can be used for items of many different sizes and ensure a tight fit preventing damage in transit for all of them. MailJacket™ cardboard capacity mailers have become the market-leading product due to their quality and efficiency. This is because items are inserted on the long edge, they glide across the smooth cardboard interiors and are quickly secured with a peel and seal closure and easily opened due to their perforated ripper strip.