KN95 respirators are high-efficiency masks (Chinese standard GB2626-2006) designed to filter $\ge$95% of airborne particles, including dust, pollutants, and bacteria. Key features include 4-5 layers of non-woven fabric, 3D structure for breathability, adjustable nose bridges, and ear loops for a tight fit.

Key Features of KN95 Respirators:

High Filtration Efficiency: Filters $\ge$95% of particulate matter, including bacteria and germs.

Layered Protection: Typically constructed with 4 to 5 layers of multi-layered non-woven, melt-blown fabric.

Secure Fit: Features an adjustable metal nose clip and elastic ear loops to ensure a tight, custom seal, which is critical for efficiency.

3D Ergonomic Design: Specifically shaped to create a 360-degree seal, providing a comfortable space for breathing without the mask touching the mouth directly.

Breathability: Designed for low breathing resistance, allowing for improved air circulation compared to standard masks.

Usage Considerations: These are generally disposable, single-use masks. They should be replaced if soiled, damaged, or if breathing becomes difficult.

Valved Options: Some models include a one-way breathing valve to reduce heat and humidity buildup inside, making them more comfortable, particularly in hot environments. Note: Valved masks may not be suitable for sterile settings as they allow unfiltered air to escape.