Our 344mm x 344mm white all board envelopes are ideal for keeping papers, card and slim items safe during transit and are perfectly sized for sending 12\" records. Made from 400gsm solidboard, these envelopes have a rigid construction that offers a great level of protection whilst being lightweight enough that postal costs are not inflated. Featuring a peel and seal adhesive strip that offers a strong, secure, tamper-evident closure, our envelopes are perfect for sending sensitive and private documents too. The smooth, white coated outer offers a highly presentable, professional packaging solution that can be printed on with postal markers or to help convey your brand. As well as being versatile and smart-looking, these envelopes are super eco-friendly; made from recycled, sustainably sourced materials, they are recyclable, biodegradable and plastic free too, making them the ideal postal packaging solution for any operation.