Amazon now allows owners of compatible cars the option to deliver packages to the trunk of their cars. This is an expansion of Amazon Key, which launched as a service that allowed customers with smart locks on their homes, or ones willing to install one, the ability to allow delivery drivers to place packages inside their homes, instead of on their porch. While many people may be uncomfortable giving a delivery person the ability to unlock their home, access to one’s car is a lot less worrisome.

In-car deliveries are available to Prime members in the same 37 cities that in-home deliveries are available. Currently, only Chevrolet, Buick, GMC, and Cadillac vehicles with an active OnStar account, and customers Volvo vehicles with an active Volvo On Call account can use the in-car delivery option.

If you have a compatible vehicle, you can open the Amazon Key app and set up your vehicle as a delivery destination. Once added to your Amazon account, you’ll be able to select “In-Car” as a delivery option when checking out on Amazon. In-car deliveries are available for most standard, 2-day, and 1-day deliveries and are not limited to Prime Now. Packages that are over 50 lbs, larger than 26 x 21 x 16 inches in size, cost over $1,300, or require a signature are not eligible for in-car delivery.

On the day of a delivery, customers will be given a 4-hour delivery window for when to expect the courier via an app notification. A second notification is sent when the delivery is on its way and a third when the package has been delivered. This lets customers ensure their vehicle is within range of the delivery location they set. If your car happens to not be in the right spot, you can select whether the courier should try again the next day or deliver the package to the building like a standard delivery. Customers can track when their car was unlocked and relocked in the app’s activity feed.