This chain letter has been circulating on the internet for some years.
Recently a version has been distributed which claims to be from the Halifax
Building Society. However, the company’s website has no warning on it and it
appears the originator of the chain letter is using the Halifax’s name to add
credibility to the message.

Sophos would like to thank Martin Overton for information he supplied
regarding this chain letter.

More information can be found at http://www.snopes.com/inboxer/scams/atmtheft.htm.

The text of the chain letter reads as follows:

The latest ATM scam involves thieves putting a thin, clear, rigid
plastic 'sleeve' into the ATM card slot. When you insert your card, the
machine can't read the strip, so it keeps asking you to re-enter your PIN

Meanwhile, someone behind you watches as you tap in your number. Eventually
you give up, thinking the machine has swallowed your card and you walk away.
The thieves then remove the plastic sleeve complete with card, and empty your
account. The way to avoid this is to run your finger along the card slot before
you put your card in. The sleeve has a couple of tiny prongs that the thieves
need to get the sleeve out of the slot, and you'll be able to feel them. The
police would like as many people as possible to be aware of this scam, so pass
this on to your friends.

Original Source : https://www.sophos.com//en-us/threat-center/threat-analyses/hoaxes/chain-letter/atmtheft