What the class numbers mean
Laser classes are safety categories based on output power. Class 3B lasers emit up to 500 milliwatts, or half a watt. Anything above that is Class IV. The class describes how much care is needed around the eyes and skin. It does not, by itself, tell you how well a device works.
Why “cold” laser?
Low-level lasers produce no noticeable heat, which is where the name came from. People often use “cold laser” for all therapy lasers, including Class IV devices that feel warm. The broader scientific term for the treatment is photobiomodulation.
How they compare
| Low-level (Class 3B) | Class IV | |
|---|---|---|
| Power | Up to 0.5 watt | Above 0.5 watt |
| Sensation | Usually none | Gentle warmth |
| Session time | Longer for the same dose | Shorter |
| Application | Often held still on points | Moved continuously over an area |
| Eye protection | Recommended | Required for patient and provider |
Is more power always better?
Not automatically. What matters is delivering an appropriate dose to the target tissue. Higher power makes that practical for larger or deeper areas in a short session, which is why many clinics choose Class IV devices. Dose, wavelength and technique all matter.
What we use
Natural Healing of Tampa Bay uses a Chattanooga LightForce XPi Class IV laser, with a 980 nm wavelength and power adjustable from 1 to 25 watts. See Class IV laser therapy for what it is used for here.