The US unmanned underwater drone seized by the Chinese navy is similar to commercial units that have been deployed by oil companies for underwater exploration and by emergency services for search and rescue, reports say.
The US Navy had used a Bluefin-21 to search for wreckage of Malaysia Airlines Flight 370, descending to 5,000 feet to scour the Indian Ocean floor.
The underwater drone is commercially available and they retail for about $1,50,000, NBC News reported. These types of gliders are generally used for environmental collection to help the Navy better understand the oceans and how sonar works. They are also used to help the Navy better conduct anti-submarine warfare, it said.