Why do we ask for the CCV#?

We ask for this information for your security, as it verifies for us that a credit card is in the physical possesion of the person attempting to use it.

Locating your Credit Card CCV Security Code:
Visa/MasterCard Your card security code for your MasterCard, Visa or Discover card is a three-digit number on the back of your credit card, immediately following your main card number.
American Express The card security code for your American Express card is a four-digit number located on the front of your credit card, to the right or left above your main credit card number.