Weapons that can incapacitate crowds of people by sweeping a lightning-like beam of electricity across them are being readied for sale to military and police forces in the US and Europe.
At present, commercial stun guns target one person at a time, and work only at close quarters. The new breed of non-lethal weapons can be used on many people at once and operate over far greater distances.
But human rights groups are appalled by the fact that no independent safety tests have been carried out, and by their potential for indiscriminate use.
The weapons are designed to address the perceived shortcomings of the Taser, the electric-shock gun already used by 4000 police departments in the US and undergoing trials with some police forces in the UK.
It hits the victim with two darts that trail current-carrying wires, which limit its range to a maximum of seven metres (see graphic). As a single shot, short-range weapon, the Taser is of little use in crowd control. And Tasers have no effect on vehicles.