The U.S. Navy awarded Bell Helicopter Textron a $240 million contract modification to manufacture and deliver 12 AH-1Z attack helicopters to Bahrain, the U.S. Department of Defense said.

The U.S. approved the sale of 12 AH-1Z Viper helicopters to Bahrain in April 2018 at an estimated cost of $911.4 million including missiles and related equipment.

The contract modification announced on Thursday, February 7 awards Bell $240,266,448 million in foreign military sales for 12 Lot 16 aircraft. Work is expected to be complete in August 2020, the Pentagon said.

The AH-1Z Viper is the latest in the long line of Huey family helicopters. The twin-engine attack helicopter is based on the AH-1W SuperCobra developed for the U.S. Marine Corps and features a four-blade, bearingless, composite main rotor system, upgraded avionics and a new target sighting system.

It first flew on December 8, 2000.

At the time the sale was approved, the Defense Security Cooperation Agency said Bahrain would use the AH-1Z to improve its capacity to deter “regional threats and to strengthen its homeland defense.” The proposed sale also included AGM-114 Hellfire precision-guided air-to-surface missiles, and Advanced Precision Kill Weapon System II precision-guided rockets.

In June, Lockheed Martin was awarded a $1.1 billion contract to produce 16 F-16 Viper fighter jets for Bahrain, and in December 2017, Bahrain was among ten foreign customers for Raytheon’s Advanced Medium-Range Air-to-Air Missiles (AMRAAMs).