Vietjet, a Vietnamese airline, has announced an order for an additional 100 Boeing 737 MAX aircraft. Based on list prices, the order is valued at approximately $12.7 billion. The carrier now has a total of 200 MAX aircraft ordered, with the initial 100 being made in 2016.

The order was previously made at the Farnborough Air Show, but were unidentified on Boeing’s website of orders and deliveries.

The 100 aircraft order is comprised of 20 MAX 8 aircraft and 80 MAX 10 aircraft. The MAX 10 is 14 feet and 2 inches longer than the MAX, providing more room in the cabin to seat passengers.

In addition, Boeing is partnering with Vietjet to provide engineering, technology, crew, and management expertise to help streamline operations.

The Boeing 737 MAX is the latest iteration of the 737 family. The MAX design features various improvements to obtain better fuel efficiency for operators. All MAXs will use the CFM LEAP-1B engine. A new winglet design also helps cut down costs by improving aerodynamics for the 737. In total, the 737 MAX introduces improvements of about 14% in fuel efficiency and emissions compared to the 737 Next-Generation (NG).

Vietjet currently operates a fleet of various Airbus A320s on 106 routes in the Asian region.