For the most part, this seems to work well, but I ran into a very frustrating experience while using this with the HP website today. Basically, it would generate a virtual number, but the number would not properly populate in the order fields - this happens periodically, so the add on allows you to copy and paste manually - not a deal breaker. However, every time I would manually enter the virtual information, Eno would reset the page and default the billing and shipping address to the same thing (which I did not want), as well as either (a) remove the item from the cart or (b) add a second item, with no way to reload the page. I eventually gave up and went to a different browser and used the real card number.