The S3 was the primary issue military gas mask in the Republic of Korea until the full introduction of the K1 in 2005(?). The mask itself was designed by the SanCheong company in South Korea. SanCheong is the largest safety equipment producer in South Korea. They have also produced the S4 and S5. The mask was originally created for the military, police, and industrial fields, but is today only used by the police and industrial fields of South Korea.
The masks were imported in small numbers and are very hard to find in the US, the rarity of these masks in other countries is unknown. They were packaged from the factory with the mask and filter in separate labelled foil packages inside of the haversack, with the manual tucked in the bag as well. The box tells of the production date, and box contents, along with general info on the mask. The mask is only rated for Chemical and Biological agents, which is particularly interesting since this was Military issue.
The mask is made of a very heavy butyl style rubber, with a textile head harness. The Rubber is very smooth on the mask, and does not irritate the face when the mask is being worn, donned, or taken off. There are only three pieces of visible stainless steel on the mask, the input clamp band, and the two screws holding the exhale valve/voice diaphragm cover on the main structure, the rest is rubber and tough gloss and flat black plastic. SanCheong is printed on the temple area, along with a size indicator on the right fore strap, the mask was issued in sizes ( Small, Medium, and Large ). Sizing takes account of average Korean facial characteristics, so size Large is similar in build and size to a medium size in European and US masks.
The entire filter and exhale assembly is located on the front of the mask, eliminating the need for left and right handed versions of the mask. The threading is STANAG 4155 compliant, allowing standardised NATO canisters to be used. The form of the exhale valve assembly makes it almost impossible to clear the mask, as there are holes wrapping around the filter input, along with all along the front of the cover and some below. The odd positioning of the filter input actually aids the user in the fact that it is very easy to thread the filter, as it hangs down at a little over 90 degrees. A large metal band seals the rubber around the front assembly, and can be taken off with the access of the lower clamp.
The eye lenses on the S3 are particularly odd, being a strange, rounded triangle set up. They provide a very large field of view, but not as good compared to others. There is a fairly large space between eye pieces, causing a blind spot along the users nose ridge. Like most masks of this era, it has an inner second seal, along with a nicely done oral-nasal cup. The oral-nasal cup is rather thin, again, made to fit the Asian facial features. It has two inhale valves with extremely thin, smooth valves. There is no sign of an air guidance system, which leads to some fogging when a filter is not attached to the mask.
Something very odd about the mask is that there is no seal to force air away from the inhale port out of the exhale valve, so in turn, air flows freely out of the inhale port, causing issues with moist air in filters. Why this problem exists is unknown. Due to this, with no filter on the mask has almost no breathing resistance due to the open hole, but the mask fogs badly with no filter on. The diaphragm on the S3 exceeds many expectations, and users can be heard quite clearly. The mask uses a completely fabric head harness with a large comfortable mesh skull cap with a small pull tab on the bottom. The straps are very long to allow a user with any length of head to wear it, but also causes there to be a large amount of strap overflow. It uses plastic buckles, and gives a very positive clicking sound when the straps are being adjusted, requiring little to no effort to snug the straps up to the head.
The mask was issued in two configurations, one came with a large green hood, hose, and filter, and one with just the filter. The first set up mentioned was for industrial use and military use in heavily contaminated environments. The second configuration is with just the filter, issued to all three fields for normal situations.
The S3 filter strikes a huge similarity to the US C2 series. The filter has markings reading SCA-HM2K1-01 The 01 stands for 2001, the production year. As far as filters go, it is very heavy. The soft bottom rubber plug goes into the bottom very easily, and the top thread also is labeled San Cheong, and has large bumps to aid in removing the cap.
It comes with a Grey Nylon carrier that has the mask model, for Chemical and Biological Agents, and Made in Korea on the outside. The American frame is smaller and the shoulder strap along waist strap both are very short. It opens with a zipper, and the inside of the bag is covered in a smooth grey waterproofing material.