The M-1 dust respirator was issued during WWII to vehicle drivers and to troops in areas such as North Africa in order to prevent the inhalation of dust or sand. It was usually used with goggles to protect the eyes as well. It is a very simple design, and seems to be very functional for its purpose. Note that this was not designed for NBC protection and will provide no protection whatsoever against NBC agents- it was meant for large particles such as dust and sand only. The harness is a simple four-point system which is adjustable- but not easily adjusted while on the head. It was most likely intended to be adjusted beforehand. The main facepiece is made out of the dust filter itself, and was channeled through an internal inhale valve. The exhale valve, which can be seen on the mask, is directly below the filter-clad inhale valve.The M-1 is fairly available today, and can be found in NIB condition without great difficulty. Expect to pay about ~$30. A neat collectible, but due to its age, it is not recommended to wear as a paint or dust mask- both because of the potential to wear down a piece of history and simply because it won't work as well as a modern dustmask. In emergencies, it would probably function decently enough.