Seal Tite® Mattress Bag Twin/TwinXL This heavy-duty mattress bag protects your mattress from dust, water, bed bugs, and other pests while in storage or transit. The extra durable 3 mil polyethylene material resists rips or tears and is connected with a double adhesive seal to protect bedding. L : 15.5 - W : 11.5 - H : 8 - W : 18