Round particulate filters, 3 M, EN 143, filter P3R, active charcoal, 20 unit(s)Round particulate filters, 3 M, EN 143, filter P3R, active charcoal Acc. to EN 143 (particulate filters). The round shape makes assembly easier because the filters can be inserted into any position using the bayonet catches. The breathing resistance has been reduced by up to 30%, making it possible to work for longer without tiring. Suitable for respiratory protection masks made by 3M: L167. 1ff N168. 1ff PT45. 1f N182. 1 HLL0. 1ff. Technical