Oura has launched Oura Ring 5, its newest smart ring as the company, which was recently valued at $11 billion and is prepping for an IPO, looks to defend its lead in the increasingly competitive wearables market and push further into preventive health.

The new ring is 40% smaller than Oura Ring 4, with redesigned sensing architecture, week-long battery life and a slimmer form factor designed to make the device easier to wear continuously. Oura says the Gen 5 ring is the world’s smallest smart ring.