Siebe Gorman Salvus

The Siebe Gorman Salvus is a light oxygen rebreather for industrial use (including by firemen and in coalmine rescue) or in shallow diving.

Underwater the Salvus is very compact and can be used where a diver with a bigger breathing set cannot get in, such as inside cockpits of ditched aircraft.

That pack is a metal plate (probably aluminium), with a webbing sheet stuck to one side to protect its user's diving suit or overall.

Its cylinder pressure gauge is on a flexible metal tube and fits in a circular webbing pouch threaded on the waist harness strap.

Early versions were originally designed for use in bad breathing conditions such as in underground mines and other enclosed spaces, where heavy concentrations of noxious gases could build up and affect the workers.

During World War I, Salvuses were used by machine gunner units on the Western Front (1915) as an interim protection against enemy gas weapons.

At the coalmine rescue on 7–9 September 1950 at Knockshinnoch Castle Colliery near New Cumnock, Ayrshire, Scotland, 115 trapped miners were equipped with Salvuses borrowed from fire stations around to bring them out through a gas-filled mine passage.