Windshield sticker

I have a rental car with this tiny sticker inside. It could look like an antenna, but there is nothing connected to it.

The notch is at the place where there is little crack in the glass, so I'm wondering if it's to relieve stress or prevent the crack from widening, etc.

Any idea what it could be?

  • Is the sticker on the inside or outside of the window? Oct 30, 2017 at 12:52
  • it's on the inside.
    – Thomas
    Oct 30, 2017 at 12:53
  • If the glass is laminate, the bullseye will be on the outside sheet of glass, while the sticker is on the inside. If they put it there to keep the crack from spreading, it's doing nothing for it. It could be an antenna, but most of the ones I've seen cover a lot more than just one stripe. Since it's not connected to anything, doesn't seem like it has much of a use to me. Oct 30, 2017 at 13:08
  • you call it "tiny". Its hard to tell from the image the actual size of the thing.
    – agentp
    Oct 31, 2017 at 3:14
  • it's roughly 10cm long, and the line on the adhesive strip is about 3mm thick.
    – Thomas
    Oct 31, 2017 at 3:16

2 Answers 2


This is definitely some kind of RFID chip. (https://en.wikipedia.org/wiki/Radio-frequency_identification)

It is there either as a toll payment id or most probably as a car identification method. Some rental cars and taxis have them as a means of quickly identifying the vehicle and maybe some info about it. Your rental company handling (renting-returning) many cars per day finds it easier to just scan this instead of manually entering the car id in some device. You are better off leaving it in peace. You are not being watched by NSA (no more than your social media use) You are not being followed. Drive safely and enjoy.


A smaller version is used for automatic ID at toll bridges. When you pass under the structure on the highway, the large antenna picks up enough voltage to power the RFID circuitry. Then the RFID sends the vehicle ID to the overhead scanner. There could be highway scanners all over, and the rental company gets a readout to confirm your driving range, etc.

  • It's in Malta, there are no readers on the highway for sure; the place is 30 years behind :)
    – Thomas
    Dec 22, 2018 at 13:47
  • 1
    Perhaps the hire car company uses RFID chips to identify it's own vehicles leaving and entering it's yard? May 20, 2019 at 10:21

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