Cotton gauzefilter (stock replacement filter). Looking almost identical to the set up of a paper air filter, a cotton gauzefilter is fitted and enclosed to a holder.
The face mask consists of double-layer non-woven cloth in which filter layer, nose bridge bar and face mask belt is set, or is made of multi-layer medical absorbent gauze.
口罩由双层无纺布中间夹过滤层、鼻梁条和口罩带构成，或由多层医用脱脂纱布经缝制而成。
3
In the 1980s, the first air intake systems were offered and consisted of molded plastic intake tubes and a cone-shaped cotton gauze air filter.