Changes

'''Filtration Plugs''' typically consist of simple plugs of porous fibres are worn in each nostril to screen out most pollutants and harmful gases. Well-crafted examples can provide protection equivalent to a respirator while poor qualitry quality variants must be replaced after five hours usage as the filter becomes clogged and unusable.{{Fn|1}}{{Fn|2}}{{Fn|3}}

*[[Rebreather]]