EXPLANATION OF DAVIS MASK CONFIGURATION NOMENCLATURE
Since Davis chose to sell kits (or configurations) and did not assign names to it's facepieces, as previously thought, I have created this page with the express purpose of clarify any confusion regarding what each kit designation refers to.
The M-1 Configuration
Despite their varying facepieces and filter attachment systems, all 3 of the setups above are reeferred to as M-1 kits, because they use a 10-inch hose running from the facepiece to a canteen-sized canister mounted on the chest of the user. The threaded fitting on the right most mask above was not manufactured by Davis, and it's original origin is unknown.
Not all M-1 configurations made with part number 3020 (chin welded facepiece, far left in the photo above) were sold under the Davis name though. Companies like La France (a maker of firetrucks) and Victor (another small safety company) would often buy M-1 kits from Davis under contract and sell them under their own names. While it is unknown what happened to Victor, is it known that La France went on to purchase many gas masks from The Mine Safety Appliances Corporation.
The M-O configuration
The M-O configuration uses a long hose, running over one shoulder of the user and connecting to a threaded canister mounted on the lower back. The hoses for these setups are invariably 3 ten-inch hoses affixed together with interior metal tubes bridging the connections.
The M-27 configuration
The M-27 configuration uses a 27 inch hose running to a carrying bag on the user's hip. This bag bears a strong resemblance to the ones used for M1 and M2 military gas masks, and it's suspected that Davis purchased surplussed bags to use for this kit.
The J-M configuration
The J-M configuration uses a single threaded filter, attached to the chin of the facepiece.
The Hose Mask (no known official designation)
The hose mask configuration is made for environments posing risks of high concentrations of gasses (that would make a filter mask impractical) or with a critically low oxygen content in the air. two hoses run from the chin of the facepiece and over the user's shoulders, where they reconnect in a union. A longer hose runs from this back to the blower chest (depicted in the right photo) where an assistant hand-cranks a pump to supply air to the user.