Walmart has announced its plan to expand drone deliveries by the end of the year.

In partnership with DroneUp, Walmart will increase its drone delivery network to 34 sites, providing the possibility to reach 4 million U.S. households across six states, according to a Walmart press release. These states include Arizona, Arkansas, Florida, Texas, Utah, and Virginia.

Expanding its drone delivery network can provide Walmart the ability to deliver over 1 million packages by drone each year, according to the release.

For a delivery fee of $3.99, a customer’s drone order can total up to 10 pounds. Between the hours of 8 a.m. and 8 p.m., customers can choose from many eligible items for delivery by air in as little as 30 minutes.

Participating Walmart stores will have a DroneUp delivery hub that includes a team of certified pilots managing flight operations for the drone deliveries, according to the company.  Once the order is placed, the item is packaged, loaded into the drone, and delivered to the customer’s yard using a cable that lowers the package.

“After completing hundreds of deliveries within a matter of months across our existing DroneUp hubs, we’ve seen firsthand how drones can offer customers a practical solution for getting certain items, fast,” Walmart stated in its press release. “While we initially thought customers could use the service for emergency items, we’re finding they use it for its sheer convenience, like a quick fix for a weeknight meal. Case in point: The top-selling item at one of our current hubs is Hamburger Helper.”

However, Walmart’s drone system does have some restrictions. Because the FAA requires that a drone be operated within view of a human operator, Walmart has constructed 30-feet-tall control towers in its stores’ parking lots to offer the drone service, according to a report by Ars Technica. This means deliveries need to happen within a 1.5-mile radius of each store (about as far as an operator in this control tower can see a drone).