robust facepiece construction adapts well to most face sizes and shapes, holds its shape well during use and is dent-resistant; color-coded headband; easily identifiable level of protection thanks to color-coded headbands according to EN 149:2001+A1:2009; the Cool Flow valve moderates temperature rise, offering users comfortable protection even in hot and humid FFP3 conditions; reliable, effective protection against ozone gas and relief from nuisance levels of acid gases (below TLV); filter half mask 9936 is a light, effective, comfortable and hygienic protection of the respiratory organs against dust, fog and annoying levels of acid gases