Amazon has announced a new shopping feature for US Prime members called Add to Delivery that lets you add additional items to completed orders that have yet to be delivered, instead of having to create an entirely new order. The feature is only available on Amazon’s app and on Amazon.com when accessed on mobile devices, and is limited to eligible items that include electronics, clothing, books, and grocery items.

Figuring out what items are eligible seems simple enough. If the item you’re viewing can be added to deliveries arriving later in the day or tomorrow, you’ll see a new blue Add to delivery button below Amazon’s standard yellow Add to cart button. Tapping the button instantly adds the item to your upcoming delivery, but if you press it accidentally, or quickly change your mind, an undo option will immediately remove the item from the order.

Amazon says the new feature is being introduced for added convenience and as part of the company’s efforts to adapt to “how people actually shop: one need at a time, as they arise.” It will also be a welcome feature for those of us who always seem to forget a critical item until after an order is completed and paid for. The last-minute added items won’t incur any additional shipping fees, although the requisite Amazon Prime membership will cost you $14.99/month or $139/year.