When a user adds an item to their cart for the first time, Remember Anonymous Cart creates a special cartid for them. The cartid is written to a cookie which is stored on the user’s computer, and the x-cart database saves the users shopping cart contents...

When a user’s shopping cart contents are restored it gets checked by x-cart to determine stock levels; Products that went out of stock since the time they were added by the user are removed automatically from the users shopping cart.