Gas filter A1B1E1 (part of the 3M Adflo blower respiratory protection system).
Fig. may deviate
Description
A1B1E1 and A2 gas filters("A", "B" and "E" - marking of filters for protection against "organic", "inorganic" and "acid" gases and vapours according to the code letters and the filter classes).
For details see PDF.
3M recommendation: Use air hose 834008 and rechargeable battery 837631