One shopper checks out with her mobile phone at a convenience store in Shanghai, June 17, 2017.[Photo/VCG]

One after another, companies are racing to set up unmanned convenience stores, such as Bingo Box, Amazon Go, convenience store chain Lawson, and Alibaba unmanned convenience stores.

Bingo Box was set up near the parking lot of the Oushang Supermarket in Shanghai's Yangpu district. It has no staff and customers must scan a QR code on the door to get in. The door locks once the shopper enters, meaning the next customer has to scan the code to get in too.

A label on each product allows customers to scan the price of each item at the electronic check-out area. Once the shopper has paid, he or she can leave the store.

You can also walk around the store without buying anything. Scanning the QR code on the wall at the entrance will open the locked door. If someone tries to leave without paying, an alarm is triggered at the door.

While not large, the store has a nice selection of goods. Another highlight is that the items are cheaper compared to other convenience stores. However, it may not win the hearts of consumers who are unaccustomed to making mobile payments.

The unmanned convenience store costs less to build and operate. For now, such stores are mainly located in high-end residential areas that are closed or semi-closed. Currently, two Bingo Box unmanned convenience stores are operating in Shanghai.