Walmart has boosted the number of stores utilizing self-service “pickup towers” that allow customers to retrieve purchases made online.

The company first introduced the kiosks at the hometown location of Bentonville, AR. They are now in more than a dozen stores scattered throughout the United States.

To get an item, customers scan a barcode on a purchase receipt, which then opens a kiosk door or starts a conveyor belt.

Walmart said the kiosks are better than pickup lockers because it is easier to adjust the size of the compartments where packages are kept.

Last month, Walmart announced the expansion of a separate program that allows customers to order groceries online and pick them up for free at a local store.

“As customers are looking for new and convenient ways to shop, we remain committed to testing innovative concepts by combining digital and physical assets that enable customers to shop when, where and how they want,” Walmart said.

Walmart is testing several other unorthodox shipping methods, including having associates on their way home deliver packages to customers.