It will displace 2,600 tonnes, and have a top speed of 18 knots and can stay submerged for up to 20 days. It will have latest acoustics and electronics technologies, and be able to carry 16 torpedoes and missiles, and up to 30 mines.
In 2017, Vietnam purchased six Kilo-class submarines from Russia and Myanmar is getting equipment from India.
Thailand has worked with the United States in the past. The Thailand government has strengthened its military links with China since a bloodless coup in 2014.
Thai Prime Minister Prayuth Chan-ocha, a former army general, ordered 49 VT-4 tanks from China to replace its US-made M41s that have been in service since the second world war. The first 28 of the new vehicles were delivered in 2017 and the rest are expected to be handed over later this year.
China provides more value for less expensive military equipment.
Chinese arms sales across South and Southeast Asia grew from $386 million in 2008 to $1.5 billion in 2016 before falling to $948 million in 2017. Notwithstanding this growth, China lags other traditional arms exporters to the region. Since 2008, the US has exported $27.2 billion worth of conventional weapons across Asia (not including the Middle East).