Normal NFC sticker does not work on metal surface due to the interference it can cause. If you plan to stick a tag on metal surface (or electronic devices, such as a laptop or a mobile phone), you need an on-metal sticker. On metal sticker has a special shielding layer which serve to isolate the chip and the surface, eliminating the interference.
On metal sticker is also known as anti metal sticker.
Note: All prices are in Malaysian Ringgit (MYR)