Siebe Gorman

Siebe Gorman & Company Ltd was a British company that developed diving equipment and breathing equipment and worked on commercial diving and marine salvage projects. The company advertised itself as 'Submarine Engineers'. It was founded by Augustus Siebe , a German-born British engineer chiefly known for his contributions to diving equipment.
Siebe plc started in the 1970s as a continuation of Siebe Gorman when Siebe Gorman started to take over other firms, to mean the new conglomerate to distinguish it from Siebe Gorman's original breathing apparatus and diving gear core business. Siebe plc was once one of the United Kingdom's largest engineering businesses. It was a constituent of the FTSE 100 Index but in 1999 it merged with BTR plc to form Invensys. Invensys was taken over by the French multinational Schneider Electric for £3.4 billion in January 2014.
Operations.
The Company was notable for developing the "closed" diving helmet of the standard diving dress and associated equipment. As the helmet was sealed to the diving suit, it was watertight, unlike the previous "open" helmet systems. The new equipment was safer and more efficient and revolutionised underwater work from the 1830s.
Colonel Charles Pasley, leader of the Royal Navy team that used Siebe's suit on the wreck of suggested the helmet should be detachable from the corselet, giving rise to the typical standard diving dress which revolutionised underwater civil engineering, underwater salvage, commercial diving and naval diving.
Standard diving suit equipment was their main manufacturing operation, producing diving helmets in copper and brass. They also made frogman's equipment for the British armed forces during World War 2, and later, sport scuba gear. See makes of rebreather.
Siebe Gorman and Co manufactured 12 bolt, 8 bolt, 6 bolt, 3 bolt, 2 bolt, no bolt, flange, and 12 bolt square corselet standard diving helmets.
Heinke Ltd in London also made diving gear and had connections with Siebe Gorman.
Siebe Gorman product list.
Rebreather equipment.
This is a partial list of some of their rebreather equipment covering military and civilian, diving and non-diving. Taken from Oxygen Rebreather Database, and afterwards edited.