originally called esi (electronic systems international), the company manufactured sub-assemblies for the agm-45 shrike and rim-7 sea sparrow missiles in 1974, and just after the vietnam war which was part of a standard arms contract for the us defense administration (dcas). the company also had a commercial repair facility of two meter portable amateur ("ham") radios from a company in new jersey called clegg, and manufactured communications helmet radios for firemen, and electronic outdoor bug zappers.