Americans already enjoy Amazon in-home delivery and keyless guest access (although some find it a dubious invasion of privacy) through Amazon Key. Now, the global conglomerate has announced a new way customers can receive deliveries: in their vehicles.

The service is called Amazon Key In-Car. Amazon Prime members with compatible vehicles may have packages delivered inside their cars when they're parked in a publicly accessible area, typically at their home or workplace.

The new in-car delivery service is now available in Houston, Dallas-Fort Worth, Austin, and San Antonio, plus approximately 30 other U.S. cities and surrounding areas. Delivery is available on tens of millions of items sold on Amazon.com, and it works with Same Day, Two-Day, and Standard Shipping.

There’s one caveat: The in-car delivery is only available to customers with a compatible 2015 or newer Chevrolet, Buick, GMC, or Cadillac vehicle with an active OnStar account and customers with a 2015 or newer Volvo vehicle with an active Volvo On Call account. Support for even more vehicle makes and models will be added over time, according to a release.

To get started, customers download the Amazon Key App and then link their Amazon account to their connected car service account. Once setup is complete and the delivery location has been registered, customers can shop on Amazon.com and select the “In-Car” delivery option at checkout.

On delivery day, the Amazon Key App lets customers check if they’ve parked within range of the delivery location and provides notifications with the expected four-hour delivery window. The app also notifies customers when the delivery is on its way and the package has been delivered. Customers can track when their car was unlocked and relocked via the app’s activity feed; they also have the ability to rate the in-car delivery.