Here is a smart breathing trainer that helps improve your athletic performance and health in general. The OPUMP Smart Breathing Trainer comes with Bluetooth connectivity. It comes with everything you need for respiratory muscles training. The device requires only 10 minutes of training everyday. Its app comes with exercises and games to keep you motivated.
The device measures your breathing flow rate and volume in real-time. It has a LED display built-in. You can find out more about it here.