ONpple works on interchangeable AirPod headphones that have health tracking capabilities to measure heart rate and stress levels.

This emerges from a new patent from the company showing how a new version of their wireless in-ear headphones could fit in any ear.

The file shows that the device slips into the ear canal and is held in place with a bendable band.

Apple's latest wireless AirPods were first launched in 2016, though some users have complained that they may easily fall out or feel uncomfortable.

Apple removed the headphone jack from its iPhone models from the iPhone 7, forcing users to buy wireless headsets.

While Apple users on a …