A waterless car diffuser without an electric type would be a passive diffuser that relies on natural airflow to disperse the essential oils into the car’s air. There are several types of passive car diffusers, including:

Aromatherapy clip diffuser:

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These are small, clip-on devices that hold a felt pad infused with essential oils. They can be clipped onto a car’s air vent or placed in a cup holder, and the airflow from the car’s ventilation system will help diffuse the scent.

Car diffuser jewelry:

These are small pieces of jewelry, such as bracelets or pendants, that have an absorbent material infused with essential oils. They can be worn while driving, and the natural heat and airflow from the car will help release the scent.

Natural wood:

it is made of natural wood and aromatherapy volcanic rock to help diffuse fragrance into air better.

It’s important to note that while these passive car diffusers do not require electricity or water, they may not be as strong or long-lasting as electric or water-based diffusers. Additionally, the scent may not be as evenly distributed throughout the car’s air. However, they can be a convenient and affordable option for those who prefer a natural and subtle way to diffuse essential oils in their car and most important thing this type easy to take and cheaper.