Don' need to preheat before using, just press and pull the mini food sealer across the bag to create an airtight seal. Any type of plastic or aluminum bag is subject to the power of sealing.Sealing more stronger without air leakage. Avoid moisture, refuse the taste of multiple foods from mixing, and keep food . The blade can help you open the express,packaging,etc faster. Very suitable and portable for use in kitchen,camping,travel,office,school. The heating sheet is hidden under the opening and protected by a slidable cover, uneasy to Press and anti-scald. The cutter is under the cover and you need to slide the button to open it. Easy to hold with one hand, and can be conveniently put into a pocket or bag. It has a magnet on the bottom to stick on the fridge, and it has lanyard on top for hung on a This chip bag sealer is made of high-quality ABS and silicone material and adopts safe structure design. Heating seal: heating sheet Power source: alkaline battery colour: green Material: ABS+silicone Size: 85x45x42mm Package Contents: 1 x Bag resealer 2 x AA batteries Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.