Just clean the , peel off the adhesive backing, press hard, and then install the magnetic accessories, which is convenient and fast. The metal strip size is measured to be approximately 9x1.8cm/3.54x0.71in. Please confirm whether the size meets your needs before purchasing. You receive 40 pieces of metal plates for magnetic mount, you can enhance the magnetic vent cover for the best seal. Sufficient quantity can meet your use needs. Made of stainless steel, reliable and not easy to deform or break. Good materials are with good performance, you can use it with confidence. Designed for non-magnetic surfaces such as aluminum, plastic or wooden vents, magnetic vent covers can be used without steel vents., Manufacturer: CTRLZS