For your safety and security, our card processing server requires that
you enter your card verification number, if one is available. The
verification number is a 3 or 4 digit number printed on your card.
If you are using a Visa, Mastercard, or Discover card, it is a 3 digit
number that appears to the right of your card number (see below).
If you are using an American Express card, the verification number is a
4 digit number that appears on the front of your card, above and either on
the left or right of the card number (see below).