US movie star Will Smith, basketball veteran Shaquille O’Neal and other investors have pledged about 17.5 million euros to the Finnish startup firm Oura Health, according to Bloomberg news.
The news outlet reports that Oura's latest funding round was led by MSD Capital raised about 4.5 million euros.
The company, which shipped its first rings near the end of 2015, said the funding will be used towards increased production. Oura's latest models of rings - which track and record a person's pulse, temperature and sleep patterns - range in price from 314 euros to more than 1,000 euros.
US computer and smartphone giant Apple is pursuing the wearable fitness market with its Apple Watch. But some industry insiders say that people often do not wear smart watches to monitor their sleep because their batteries are usually being recharged overnight.
Oura's rings, according to the company, can be charged in less than an hour with a battery life of around 2 to 3 days.
A market research firm said the wearables and health tracker market is expected to grow to nearly 10 billion euros by 2025, according to Bloomberg.