Abstract: An anti siphon device constructed of polyethylene balls and placed within a fuel filling neck, above the fuel tank. The anti-siphon device is comprised of an outer perforated ball with an inner axis mounted ball on the interior. The device will allow the free flow of fuel while blocking siphon mechanisms to pass through and reaching the fuel stored below. The device is inexpensive to manufacture and install and does not negatively affect the vehicle operation or fuel refilling capacities.