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ARTICLE 2
Comparative Analysis - The US M17 Series and Its Copies

_____In the late 1950s, the US Army designed and standardized the ABC-M17 Chemical-Biological Mask. This mask was the first to incorporate dual filter elements housed in two bilateral cheek pockets. This feature eliminated certain difficulties with head mobility and also enabled both right and left handed weapon sighting. The one major drawback however, was that the two internal filter elements were not easily exchanged in the field. To swap filters the wearer had to remove the mask and perform the rather difficult and time consuming task of both extracting the spent filters and inserting fresh ones. This is one of the key factors that lead to the replacing of the M17A2 series masks in the early 1990s. Despite this problem, the M17 was just as successful as it's predecessor, the M9A1. The M17 was copied by at least 4 countries, possibly more.

THE US M17 SERIES (FROM LEFT): EARLY MANUFACTURED M17 (1958), THE ABC-M17, THE M17A1/A2

_____The first prototypes of the M17 were made in the late 1950s, and the M17 was standardized in 1959. The early version of the M17 (above left) is possibly a prototype, considering the date stamp of 1958 and the presence of the C.W.S. symbol molded into the front of the mask (see below left). The M17 went through two revisions. In 1966, the M17 was upgraded to the M17A1 after the addition of optical insert supports, a drinking device and a resuscitation tube. The M17A1's drinking device was a smart mechanism that allowed a canteen to be attached to a tube outside the mask. The canteen could then be inverted so that the thirsty soldier could suck water in via an angled straw on the inside of the mask. The straw could be moved toward the wearer's lips via a small knob on the front of the mask (see below right). The ability to consume liquids while wearing a gas mask soon became a standard once it was established that it could be done. While the idea of performing CPR between two masked soldiers was novel, the resuscitation tube that was issued with the M17A1 proved to be complicated and often jeopardized the integrity of the mask's airtight seal. The resuscitation tube was eventually phased out, with the standardization of the M17A2 in 1983. In addition to the deletion of the resuscitation tube, a size extra small (XS) was added. Aside from these two changes, the M17A1 and M17A2 remained structurally identical.

CLOSE-UP - THE FRONT OF THE EARLY M17

CLOSE-UP - THE FRONT OF THE STANDARD M17

CLOSE-UP - THE FRONT OF THE M17A1/A2

_____The closest copy of the M17 was manufactured by Poland (below, 2nd from left), and designated the MP-4M. The face blank mold, head strap configuration, intake caps, and exhale valve/voicemitter assembly were all virtually identical. Only the color and mold markings are different. Another copy, the Bulgarian PDE-1 (below left), was also very close in design to the original US M17. However, it used a rubber head harness and a different exhale valve system. On the US M17, exhalation was directed downward through the bottom of the mask via four slots in the rubber exhale valve cover, while the PDE-1 directed expired air through a valve on the front of the mask which was protected by a threaded metal cap. This method was also used on the Czechoslovakian M10 (below, 2nd from right). The Czech M10, yet another close copy of the M17, was later replaced by the widely distributed M10M. The Czech M10M is the only known copy to incorporate a drinking system. The M10M's drinking tube was configured much differently than the US M17A1/A2 (see comparative view below), but worked in basically the same way. A nice feature of the M10M's drinking tube is that it was considerably longer than that of the M17A1/A2 giving the wearer more freedom when attaching the canteen. Perhaps the most interesting aspect of the M10M copy is that it used a single hard plastic cap to cover the exhale valve/voicemitter/drinking assembly instead of a molded rubber cover like the M17A1/A2. The M10M was issued in large numbers in both Czechoslovakia and East Germany and is quite common on the surplus market today. At least one other M17 copy was made in Japan (not shown). Like the Polish version, the Japanese version was very close in design to the original M17. However, the Japanese version was made of green rubber, and the intake valve caps were similar to those used on the Czech M10 and the Bulgarian PDE-1.

M17 COPIES (FROM LEFT): THE BULGARIAN PDE-1, THE POLISH MP-4M, THE CZECH M10, THE CZECH M10M

THE US M17A1/A2'S DRINKING TUBE

THE CZECH M10M'S DRINKING TUBE

_____The M17 and all of its copies used dual filter elements, often referred to as "pork chop" filters, due to their shape (see below). These "pork chop" filters were all held in cheek pockets in the same way for all of the M17 masks and the copies. However, all of the different filters were kept in position by inlet valve caps that were attached from the outside of the mask, either by snapping on or screwing directly into the filter elements. Because these caps are all different and because the position of the openings in the filter elements are slightly different for all of the masks, the filters are not interchangeable among the different M17 type respirators.

PORK CHOP FILTERS (FROM LEFT): US, POLISH, BULGARIAN, CZECH (M10), CZECH (M10M)

_____As for accessories, the M17 series mask came with a butyl rubber hood that covered the wearer's head, neck and shoulders (below left), a water proofing bag and a pair of eye lens outserts. The eye lens outserts were attached over the eye pieces after the butyl hood was in place (below left). The M17A1 used the same setup but also included the resuscitation tube. The Czech versions also came with protective rubber hoods and eye lens outserts and it is likely that the other copies came with similar hoods as well.

M17A1 FITTED WITH PROTECTIVE HOOD AND EYE LENS OUTSERTS

M10M FITTED WITH PROTECTIVE HOOD AND EYE LENS OUTSERTS

_____Overall, the US Army M17 Chemical-Biological Mask proved to be influential in respirator design technology, as it was copied in Czechoslovakia, Poland, Bulgaria, Japan and possibly in Taiwan. Despite the success of the M17, the M17A2 was finally phased out and replaced by the US Army M40 in the mid 1990s during the final stages of the Gulf War.