If you've ever wished a box of diapers could just magically appear in your car's trunk, you're in luck.

Amazon is now delivering to parked cars, and parents are loving it.

It's part of the Amazon Key service for Prime members. The home version (that lets delivery services slip into your house to drop Amazon boxes when you're not there via a special smartlock and camera) has been going on for awhile, but Amazon just recently announced the in-car component which is now available in 37 across the U.S.

Amazon gave a few Prime members early access to test it out, and the beta parents seem pretty pleased.

"This is my first time using it, I needed a few birthday presents for my daughter and thought this would be the perfect use because she won't find them and they won't get stolen from my doorstep," said one mom who filmed her first delivery for a YouTube video, as she opened her trunk to reveal an Amazon box.

Another mom featured in the YouTube video has a totally relatable reason why she appreciated having her package dropped in her parked car, rather than on her doorstep (which her dogs are apparently protective of).

"The dogs didn't wake up my kids, the kids took their nap, it was really great," she says.

The system is great for parents with dogs who feel the need to alert to delivery people, but it's also great for parents who who work outside the home and don't want to have their packages delivered to the office. Nobody wants to be paged to reception to pick up a delivery of diapers or toilet paper, and with this in-car delivery service, you can just leave work at the end of the day and find your stuff in your vehicle. No need to get the front desk involved.

The delivery people don't have access to your car all the time, they just get a one-time access code to open it for that delivery. And when the delivery does make it into your trunk you get a notification.

According to Amazon, there's typically a four-hour window for In-Car deliveries, and your car doesn't even need to be parked in your driveway or a specific parking space at work. You've just got to park within two blocks of your selected delivery address, in a street level spot. Delivery drivers can then find it with GPS.

"Delivery drivers cannot access vehicles parked in garages with restricted entry. Additionally, vehicles that are parked in multi-level or underground garages do not provide sufficiently reliable GPS information for in-car delivery," Amazon notes in its FAQ.

Unfortunately, this cool car delivery scheme isn't available to all Prime customers—you've gotta drive a car that's compatible with the Amazon Key system. Right now, that means a 2015 or newer Chevrolet, Buick, GMC or Cadillac with an active OnStar account, or a 2015 or newer Volvo with Volvo On Call.

Amazon plans to add support for additional vehicle makes and models, and expand the Amazon Key In-Car service to more U.S. cities over time.

You might also like: