[ Way Of Breathing Exercise]:The breathing exercise trainer is refers to increasing strength during "OUT" and "IN" which exercising the muscles and improving exercise endurance.Our trainer is a scientific and efficient Breathing Exercise Trainer.If beginners cannot control it well, they can wear the included Nose Clip to help you practice. [Application Range Of Reference Levels]: A-D Level is suitable for Breathing Exercise; E-F level is suitable for daily exercise; F level is suitable for professional athletes (the above is for reference only, and varies from person to person).Control well your breathing to improve the quality and effectiveness of the exercise. [8-Level]:The Letter Knob is for adjusting "IN" (A-H levels), and the Digital Knob is for adjusting "OUT" (1-8 levels),you can gradually increase the level after regular breathing exercise training.It can be used for various training methods such as "OUT" training, "IN" training or a combination of both training methods.It is recommended to start from a low level when using it for the first time. [Exclusive Training Partner]:Our product provides funny application training, and the application's animations guide breathing exercise which making it easy to persist in breathing exercise training. [Exclusive Application Training Guidance]:It providing professional training modes to guide you in a cyclic and gradual manner, gradually increasing strength training as your breathing ability improves.You can also set scheduled reminders for training, record the content data of your training, and even customize your own training mode from it. Colour:B:Black Material:Food Grade Silicone + PC + ABS + Stainless Steel Package Contents: 1 x Breathing Exercise Trainer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.