Thailand has signed a contract to buy Hermes 900 unmanned aerial vehicles (UAV) made by Israeli defense electronics company Elbit Systems for 4 billion baht ($107.67 million), the Thai navy said on Wednesday.

The navy did not say in its statement how many drones it would buy, but said a budget had been set to procure the system over four years, between 2022 to 2025.

The Thai navy said the drones would be used to patrol the sea to protect the country’s maritime sovereignty, shipping routes and assist in sea rescue operations.

The Hermes 900 is a medium-sized drone, which has the endurance to fly for over 36 hours and up to 30,000 feet (9,144 m) and can carry a maximum payload of 350 kg (771.62 lb), according to the company’s website.

The drone system is used in many countries including the Philippines, Switzerland, the European Union and Canada.

In 2017 the Thai army purchased Elbit Systems’ Hermes 450 drones, the previous model to the Hermes 900.