Conventional NFC Tags don't work when applied to metal surfaces. Because NFC Tags work by electromagnetic induction,metal can easily interfere with their operation. The another reason is NFC Tags don’t work on metal is that the metal surface behind the tag acts as a ground plane and reduces the performance of the tag’s antenna,effectively stopping it creating the current needed to power the chip.NFC Tags can never work behind metal and if placed directly onto metal,then you need to use a special ‘on-metal’ tag.On-metal (or Anti-metal) NFC Tags are specially manufactured with a layer made of ferrite, so that they can work also if sticked directly to a metal surface. This product is simple adhesive ferrite, in different formats, which can be applied under the Tags that you need to be apply on a metal surface, such as a plate, a machine, etc. Keep in mind that ferrite is a magnetic shield, so NFC Tags can be read or written only from the other side. Ferrite has a thickness of about 0.2mm 0.4 mm or others. It can be cut with scissors or cutters. The following products have a special isolation layer allowing them to work on metal,for instance when placed on a metallic laptop case or other metal environment.