Our M1 Expandable Capacity Envelopes measure 219 x 155 x 70mm and are almost identical to the cardboard envelopes you receive from Amazon, simply with a plain print design. These versatile corrugated cardboard mailers have been consciously crafted with eco-friendly materials and offer expandable space to accommodate various items including books and electronics while ensuring their protection during transit. Simple to use and environmentally conscious, these cardboard envelopes are a reliable choice for those seeking to minimise their environmental footprint without compromising on quality or convenience.