EN148

Describes various standard thread connections frequently used in RPE.  Most common is EN148-1, which is the 40mm-thread connection known more commonly as DIN40 or NATO standard, and this is often used with full face masks and filter canisters.  If a mask is approved with a standard EN148-1 thread, it can be fitted with any approved standard thread filter, subject to the filter weight restrictions. This “mix and match