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Free-Cap – 19-channel EEG/QEEG cap, semi-dry, Ag

Free-Cap – 19-channel EEG/QEEG cap, semi-dry, Ag

The Free-Cap with silver (Ag) electrodes is an EEG/QEEG cap laid out to the international 10–20 system. It measures electrical brain activity without gels or pastes — a simple saline solution is all the electrolyte you need.

One cap covers recordings from 1 to 19 channels. Purpose-made sponges (Peak Pads) hold the moisture steady for the length of the recording, which keeps contact quality stable. In practice you can usually reach a good impedance range quickly.

Suited to frequency-band training and qEEG. For SCP, ISF and ERP recordings we recommend the Free-Cap Peak Performance with Ag/AgCl electrodes.

Class I medical device under the EU MDR. Developed by Thomas Feiner, patented.

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Delivery time approx. 1-4 working days

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  • Highlights
  • FAQ
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The Free-Cap was developed and patented by Thomas Feiner, QEEG-D and founder of the Institute for EEG Neurofeedback. It uses Peak Pads soaked in saline to improve conductivity between scalp and electrodes — with no gel or paste at all. Studies in which recordings were made with the Free-Cap are listed in the section on scientific publications.

What you get:

  • Clean to use: no sticky residue in the hair — clients can head straight back into their day
  • Quick to set up: saline electrolyte and Peak Pads make for a fast fitting
  • Dependable impedance control: optimal impedance values are reached quickly and hold steady through EEG and QEEG recordings
  • Flexible layout: freely movable electrode holders for 1 to 19 channels following the international 10–20 system
  • Comfortable to wear: soft sponge materials and elastic bands
  • Built to last: components can be replaced individually, which keeps the cap economical over the long run
  • Broad compatibility: works with many common systems (BrainMaster, Q20, Cognionics CAMP and Mitsar among them); depending on the system, a matching adapter or cable may be needed

If you have questions about compatibility with your amplifier, we are glad to advise.

Where it is used:

  • Neurofeedback training with frequency-band protocols
  • EEG and QEEG recordings in clinical settings
  • Peak performance and wellness applications
  • Research and teaching

For SCP, ISF and ERP recordings we recommend the Free-Cap Peak Performance with Ag/AgCl electrodes.

The Free-Cap is a Class I medical device under the EU MDR (2017/745), intended for clinical use by qualified professionals. It is in use worldwide, including in the USA, Germany, Spain, Portugal, India and Puerto Rico.

Do I need to wash my hair after the training?

No. Since the Free-Cap works exclusively with a light saline solution, no sticky residues are left behind. This is ideal for clients who have appointments directly after training.

Do I need special accessories for the Free-Cap?

No, you only need conventional table salt and tap water to prepare the electrolyte solution.

Is the cap also suitable for children?

Yes, thanks to the flexible adjustment options and the absence of sticky gel, acceptance among children is significantly increased.

Why is it useful to have different EEG caps?

People have different head sizes and shapes, so different cap sizes ensure a good fit and stable electrode contact. A poorly fitting cap can lead to measurement errors or signal noise.

For saline semi-dry electrodes, the saline solution-moistened electrodes dry out over time and the signal quality decreases. Having multiple caps allows one to be prepared anew while another is still in use, enabling quick changes and consistently high data quality.


Which EEG cap sizes are recommended for adult participants?

The sizes are based on head circumference:

- S (47–52 cm): for smaller head sizes

- M (52–57 cm): suitable for most women and small to average men

- L (57–62 cm): suitable for most men and larger heads
In practice, most women need size M and most men need size L. However, it is important to keep at least one small cap (S) on hand to ensure correct electrode placement according to the international 10–20 system.

How should the daily handling of sponge electrodes (saline semi-dry) be organized?

At the beginning of the day, several sets of sponges are prepared in saline solution. A fresh set is used for each person. At the end of the day, all sponges are cleaned and air-dried.

This ensures:

- stable and low impedances

- good hygiene between applications

- long-term good contact quality and comfort


How is the hygiene of the EEG caps ensured?

The caps can be cleaned with a mild disinfectant or hand-washed if necessary. With good ventilation, they usually dry within about 30 minutes.

Which accessories are recommended for optimal use?


Recommended accessories include:

- Peak Pads (10–30 depending on use)

- Skin preparation gel and cotton swabs

- Saline solution or salt tablets

- Pipettes and spray bottle

- Spare parts such as chin strap and electrodes

How long do EEG caps last and how can their lifespan be extended?


With proper care, caps last about 100–200 sessions or 1–2 years. Rotating multiple caps, thorough cleaning, and complete drying significantly extend their lifespan. In addition, a standardized 0.9% saline solution should be used to avoid material damage.

  • 1 mesh cap with 22 silver (Ag) electrodes in total: 19 recording electrodes, 2 reference electrodes (A1, A2) at the mastoid positions, and 1 ground electrode
  • 23 Peak Pads
  • 1 chin strap
  • Dinc, L., Rybski, D., & Dineen, J. (2025). The effects of alpha/theta neurofeedback on mood, anxiety, emotion regulation and trait impulsivity. Brain Research. Article
  • Pérez-Elvira, R., Rodríguez Ledo, C. R., Salgado-Ruiz, A., Agudo Juan, M., Quiroga Méndez, P., Dragomir, A., Costea, R., & Neamțu, B. (2024). EEG Activation During a Mindfulness Session and Its Effects on Memory Encoding. NeuroRegulation, 11(2), 112–127. Article
  • Collura, T. F., Keizer, A. W., Pérez-Elvira, R., Warner, S., & Feiner, T. (2023). Electroencephalographic imaging and biofeedback training using Z-scores: Databases and LORETA-based methods. In Introduction to Quantitative EEG and Neurofeedback (pp. 35–61). Elsevier. Book chapter

What makes Free-Cap Peak Performance special?

Silver electrodes (Ag), peak pads and electrode holders

Thanks to the Peak Pads,

which are an integral part of the system, this EEG cap is particularly well suited for reliable EEG recordings and neurofeedback training. The pads absorb and store the saline solution required for these applications. As they remain moist, stable conductivity between the electrodes and the scalp is ensured. This keeps impedances low and constant, and signal recording remains stable. In addition, the Peak Pads adapt optimally to the electrode holders.

Thanks to the flexible design of the electrode holders

the electrodes adapt to different head shapes, ensuring reliable contact while maintaining the 10-20 system.

Thanks to the double-layered design of the chin strap

the wearing comfort is significantly improved. One side consists of a thin, sponge-like textile material, the other of soft hook-and-loop material. The double seam ensures additional durability, and the soft material guarantees a pleasant, soft wearing experience.

Here's what our customers say about Free-Cap:

Amy Warren

A fantastic invention... I have the highest praise for the Free-Cap. Once you've used it, I can't imagine ever wanting to go back to the glue method. In my experience, the connectivity is better, even with ISF. I've found it works well on all hair types. Both clients and technicians are thrilled.

Dr. Robert W. Thatcher, Ph.D., CEO Applied Neuroscience, Inc.

Thomas Feiner's EEG caps are a new, excellent, and necessary innovation. The cap is easy to put on and comfortable. A unique feature is the ability to simultaneously record the EEG while applying stimuli and other treatment modalities .

Dr. Dick Genardi, Ohio

... Neurofeedback practitioners need to be aware of this cap, especially those performing whole-head assessments, 19-channel measurements, and Loreta.


The Free-Cap is so much faster to use, easier to achieve good low impedances, and much more comfortable for the patient. It's also an advantage with 4 channels or fewer. I have a DBA, so I can use your full-cap version with my Atlantis.


What I particularly like is that I can lift the electrode, apply NuPrep and put the electrode back, and the impedance drops - without the patient feeling uncomfortable.


I hope your cap is a success. You deserve to make a lot of money with it. A great contribution.

Dr. Doron Todder

I really like the cap and you get a great signal in no time!

» to application videos on YouTube

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