The S6, or Service Respirator No. 6, officially designated Respirator, NBC S6, was developed in the 1950s by the Defence Science and Technology Laboratory, Porton Down and was manufactured by the Birmingham & Leyland Rubber Company. The S6 gained notoriety when seen being used by Britain’s Special Air Service (SAS) during the widely and thoroughly documented Iranian Embassy Siege on 5 May 1980.


SAS personnel standing beside Margaret Thatcher while wearing S6 gas masks


The features of the S6 include the very innovative inflatable air seal around the inside of the facepiece. It also had an early design of an oral-nasal cup that was built into the mould of the mask, not a separate piece extending from the interior of the facepiece to cover the nose and mouth. It features a six-point semi-elastic head harness with easily adjustable metal buckles.

A left-handed variant of the S6 was also used, with the filter being threaded onto the right-hand side of the mask. These particular models also have 'LH' (left-handed) imprinted on their rubber.

The mask provides an excellent field of vision using larger eyepieces in the shape of half-rounded rectangles.

Additionally, the S6 is made of soft black rubber. The mask uses a side-mounted filter to the left of the mask, making it much easier and more natural to shoulder a firearm for right-handed soldiers. It was very much liked by the British military for its comfort and very low breathing resistance.

Sometime around 1966, a prototype 'Extra-small' size was tested.

The S6 was issued in the 58 pattern haversack originally (1966 - c.1972) before being replaced by the Mk II haversack. The original 58 pattern haversack was made of a canvas cotton blend. This presented a huge decontamination issue - the haversack could potentially soak up chemicals and the small cotton fibres were thought to be capable of trapping deposits of deployed NBC weapons. The Mk II haversack was made of nylon coated in polyurethane which was thought to make decontamination much easier.

Turkish Issued S6 Variant

At the end of 1970s Turkish Armed Forces demanded S6 masks for their CBRN response teams and Military from British Armed Forces. After several parties granted to MKEK, MKEK distributed S6 masks with the name of SR6 to TSK. Until the first period of 1990s TSK used this mask actively. Later on, MKEK developed their own S6 copies such as SR6M, SR10ST and SR10 Panaromic for military and law enforcement use throughout years. MKEK stamped these masks with 'MKEK' stamps instead of British Markings.
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