 A number of manufacturers seized on the technology to implement it in cells with conventional flat plates.In the mid 1980’s, two UK companies, Chloride and Tungstone, simultaneously introduced ten year life AGM batteries in capacities up to 400 Ah, stimulated by a British Telecom specification for batteries for support of new digital exchanges.In the same period, Gates acquired another UK company, Varley, specialising in aircraft and military batteries.