"These extreme secrecy efforts are in relation to very controversial, local government surveillance practices using highly invasive technology," said Nathan Freed Wessler, a staff attorney with the American Civil Liberties Union, which has fought for the release of these types of records. "If public participation means anything, people should have the facts about what the government is doing to them." Harris Corp., a key manufacturer of this equipment, built a secrecy element into its authorization agreement with the Federal Communications Commission in 2011. That authorization has an unusual requirement: that local law enforcement "coordinate with the FBI the acquisition and use of the equipment." Companies like Harris need FCC authorization in order to sell wireless equipment that could interfere with radio frequencies. A spokesman from Harris Corp. said the company will not discuss its products for the Defense Department and law enforcement agencies, although public filings showed government sales of communications systems such as the Stingray accounted for nearly one-third of its $5 billion in revenue. "As a government contractor, our solutions are regulated and their use is restricted," spokesman Jim Burke said.