FFP1: Non-toxic solid and liquid aerosols.<br> FFP2: Solid particles and liquid aerosols of low to medium toxicity.<br> FFP3: Solid particles and liquid aerosols of medium to high toxicity.<br> R: Reusable - for reusable masks.<br> NR: Non-Reusable - for disposable masks.<br> D: D marking shows that the mask has been tested against Dolomite dust - (Dolomite test).<br> This means that the breathing resistance only increases slowly in line with the absorption of dust.