Sixty officers in a Welsh police force have been trained to use Taser stun guns to subdue violent suspects.
The Taser works by stunning a suspect
Gwent Police has 20 Tasers, which can fire a 50,000 volt electric current, rendering the target incapacitated for five seconds.
The force issued the Tasers on Monday and said they were a "less lethal option" than using live firearms.
Amnesty International claims the guns have been linked to more than 70 deaths in America and Canada.
All four police forces in Wales look set to deploy the stun guns.
Tasers have already been used by North Wales Police.
On Sunday, it emerged the Dyfed-Powys force was training officers to use the weapon, while South Wales Police says it will probably introduce it shortly.
The Tasers work by firing two darts up to 21 ft at a target, each trailing a wire which delivers a high-voltage shock that can disable suspects in order for them to be arrested.
Officers can reload the Taser in seconds
The electrical current can penetrate clothing up to two inches thick and lasts for five seconds.
If the officers need more time to control the suspect, further five second bursts can be administered.
Sergeant Jerry Warman, of Gwent Police, trains officers to use the Taser.
He has been shot with a Taser and said that the effect of the shock was instant.
"It is quite hard to describe what it feels like - it is like a pain that radiates in your whole body starting at the head," he said during a demonstration of the weapon on Monday.
"You can't move - it is like it paralyses you.
"You know exactly what is going on but it is like it shuts you down.
"As soon as it stops, you are fine again. Some say you can feel a bit of a tingle after but generally you are so happy that it has stopped you don't notice it.
The barbs fire from the Taser at around 100 mph
"It is a less lethal option for us to use - it gives us a lot more flexibility to deal with people who have the potential to be violent," he added.
His colleague, Pc Grayson Church has also been involved in training officers to use the Taser.
He said that it would only be used by armed response officers and would be carried in the two armed response vehicles which are on call 24 hours a day with the force.
Each Taser would be carried with two cartridges, which takes an officer just seconds to reload.
"We would use them in situations where someone is carrying a weapon like a knife or a sword or a bladed instrument," said Pc Church.
"They are giving us the chance to try and stop someone without having to resort to a live firearm," he added.
The Gwent force deploys the armed response vehicles to approximately 100 incidents a year. It has only used its baton guns in two incidents since they were introduced in 2003.