If there is overlap, use the immediate smaller size.
Our headcaps have been developed to accommodate the vast majority of users. They are specifically designed for fast and efficient application, reducing the need for individual electrode position measurements, simplifying setup, and ensuring stable electrode contact throughout the session.
To achieve this balance between ease of use, reproducibility, and reliable signal quality, certain trade-offs are unavoidable. In rare cases (reported in less than 0.1% of users), a perfectly tailored anatomical fit may not be achieved for every head morphology.
If you are experiencing a situation in which the recommended size feels too tight, while the next size up results in visible air gaps between the scalp and the cap, we suggest the following mitigation strategy:
You may use the larger headcap and secure it firmly with a headwrap. Properly tightening the headwrap will help eliminate air gaps, improve scalp contact, and maintain stable electrode positioning during the session.
If needed, we would be happy to review photos of the setup to provide more specific guidance and ensure optimal performance.