What happens if the breath chamber doesn't fit my face properly?

If the breath chamber doesn't seal against your face—particularly at the nose bridge or cheekbones—exhaled breath will escape through the gaps and rise toward your goggles, significantly reducing the anti-fog benefit. This is the most common reason breath box balaclavas fail to meet expectations. If you experience this, try a different size or a different brand, as chamber shapes vary. Some models have adjustable nose bridges or flexible chamber edges that can improve the seal for different face shapes.