DO NOT Cut Lip-Seal Flap
The Lip Seal Flap is designed to help you get the ideal seal between your lips and the MAXIMUS device for maximal airflow through the device and maximal performance gains. If you cheat and breathe through your nose, you will negate most of the benefits because breathing through a nose, not through the device, is easy and will not elicit improved performance.
As stated in instructions for use, breath only through the device, never your nose or unsealed mouth, for maximal benefits and results in improvement.
If you find yourself cheating through the nose or mouth, lower your resistance level until you can use it for the entire workout.
When exercising, not using the device, you should always focus on deep breathing through your nose as this is preferred for the many benefits nasal breathing provides.