a1c47b6d_ation__NVP____PayPal_Developer__Field
[Description] (Required) The timestamped token value that was returned in the SetExpressCheckout response and passed in the GetExpressCheckoutDetails request. PayPal also appends the token as a GET parameter named token to your RETURN URL when redirecting the buyer back to your website from paypal.com. Character length and limitations: 20 single-byte characters. [Field] 
TOKEN
DoExpressCheckoutPayment API Operation (NVP) - PayPal Developer
Field