Twin Mattress Bags protect bedding from dirt, moisture, and surface abrasion during storage, moving, returns, and delivery handling. This 39" x 9" x 90" 4 Mil poly bag is sized for twin mattresses and includes a 9" side gusset to give the bag room to fit over the mattress profile without forcing the film at the corners. The 4 Mil gauge adds tear and puncture resistance for heavy duty mattress transport, especially when mattresses are handled by crews, stacked in trucks, or moved through warehouses. For operations that package both mattresses and foundations, 3 Mil bags are often used for box springs because the lower weight can be enough for lighter handling needs, while 4 Mil construction is the better fit when the mattress needs more abuse resistance in transit. Butterfly vents help improve packing efficiency by letting trapped air escape as the mattress slides into the bag or as the covered mattress is stacked.