Wilcox Exhaust Valve Kit for M40/Millennium Mask
Designed to adapt the facepiece for use with SCBA systems by providing a spring-loaded exhalation valve to provide the proper backpressure to use a lung demand regulator.
The M40/Millennium variant is similar to the M45 version (at left) in many regards, but has several notable differences -
The main outlet housing is made of CNC machined Delrin, as opposed to injection-molded glass-filled nylon
The same is a snap-on removable design, where the M45 version would have been permanently glued in place
The primary outlet valve disk must be removed from the mask in order to use the adapter (since unlike the M45 version, it does not seal against the walls of the valve body, so it seals on the valve seat instead)
The use of machined Delrin was more than likely due to its mechanical properties making it a more suitable material for a snap-on design rather than glass-filled nylon
While the official designation refers only to the M40 Mask, there are much more of these seen on MSA Millennium facepieces. Furthermore, the position of the drink tube storage port would place it pointing straight up if installed on an M40’s outlet valve, due to the position of the outlet cover lugs and the corresponding cutouts on the adapter.
Ignoring that this arrangement would block the installation of a VPU, it’s unclear if the M40’s drinking tube would even be able to reach the adapter’s storage port, given how short the former is.
I’ll update once @mou1age and I get a chance to run down to the storage unit and grab one of our M40’s.
The only other example of the M40/Millennium Exhaust Valve Kit that I know of resides in the archives of Avon Protection’s UK Headquarters, but more presumably exist somewhere within Wilcox’s HQ as well.
Above: The only known potential photo of the M40/Millennium Exhaust Valve in use, Delta Force Breacher Training, c.2004-2005. The third operator from the left is clearly wearing an MSA Millennium while the rest have Avon XM53 Masks. All are wearing a custom SCBA system.
