Avon Rubber, the UK industrials group, will supply American Special Forces with chemical and biological protection masks after clinching a $246 million (£186 million) US Department of Defense contract.
The mask, known as the M53A1, protects against radioactive dust and biological weapons.
The deal will run for up to seven years and includes self-contained breathing apparatus.
Chief executive Paul McDonald said the deal showed Avon’s “ongoing focus on technological excellence”.
In January it won an order from the US for M69 aircrew masks used by fighter pilots.
Avon, which has a £400 million market valuation, was founded in 1885 and originally made rubber for tyres and conveyor belts.
