World Rugby say that the ball, manufactured by Gilbert, has "performance and innovation at its heart" and claim it is the "most technologically-advanced sevens ball on the planet".

The new ball was developed specifically for the sevens game and features a patented "Gilbert Synergie XV-6 grip", which is said to offer enhanced grip to suit the faster-paced nature and handling of rugby sevens.

Both the match balls and official replicas have been given a tournament-specific look with a picture of the Golden Gate Bridge, a symbol of host city San Francisco, emblazoned on the surface.

World Rugby chairman Bill Beaumont complimented Gilbert on their design.

"We are delighted to be partnering with Gilbert for Rugby World Cup Sevens 2018 in San Francisco," he said.

"Their passion for innovation and performance as a field leader is perfectly suited to a tournament that will drive performance and fan experience innovation.

"The ball looks great and will enable the world's top sevens players to showcase their talent on the biggest stage.

"I am sure it will also prove popular with fans."

Richard Gray, director of sales and marketing at Gilbert Rugby, added that he was looking forward to the competition.

"For many years Gilbert have supported the growth of the game in the US and, as rugby grows in popularity from the east to west coast, we are delighted to continue the journey with our American friends," he said.

"The hosting of Rugby World Cup Sevens 2018 in San Francisco is a major step forward for the game in the US and we are proud to have been selected as the official ball supplier."

The Rugby World Cup Sevens will take place at AT&T Park in San Francisco, from July 20 to 22.