Threads
Internal threads
Dimensional tolerances
Thread gauges
Plug gauges
Thread pitch
External threads
Breathing apparatus
Threaded components
Masks (protective clothing)
Radius
Diameter
Dimensions
Safety devices
Height
Gaskets
Respirators
Link: BS EN 148-1:2018 Respiratory protective devices – Threads for facepieces Part 1: Standard thread connection
Source: BSI Standards
