Police have deemed security for the G8 and G20 summits the largest operation of its kind in Canada.

Officials have bulked up their security arsenal with sound and water cannons, tear gas canisters and rubber bullets. Protesters have complained that some of these security measures are too drastic and pose the potential to cause permanent physical damage.

Here is a closer look at some of the crowd control measures the police may turn to in the event of rioting.

The ARWEN 37 (Anti-riot weapon Enfield)

An OPP officer trains with the ARWEN 37, a weapon that fires plastic bullets and tear gas to quell violent protests. (CBC)This device was developed in 1977 to address crowd control turmoil in Northern Ireland. The loaded weapon, weighing 3.8 kilograms, can fire tear gas canisters and plastic bullets to a distance of up to 100 metres. Bullets will travel at speeds of up to 74 metres per second. The ARWEN 37 has been used by law enforcement agencies in the U.S., Singapore and in Canadian cities including Vancouver, Ottawa and Victoria. ARWEN weapons are made by Police Ordnance in Markham, Ont.

Tear gas

Tear gas, released to drive back crowds, is typically composed of chemical compounds chloroacetophenone (CN) and chlorobenzylidenemalononitrile (CS). The gas irritates the mucous membranes of the eyes, nose and mouth and can cause tearing, blurred vision, runny noses, redness, rashes, nausea and vomiting. But the effects are typically short-lived, waning after 15 to 30 minutes.

LRAD (Long-range acoustic device)

A police officer with an LRAD-X 100 acoustic communication device, known as a sound cannon, during a demonstration of G20 security and crowd control measures in Toronto. (Frank Gunn/Canadian Press)Sometimes referred to as sound cannons, the LRAD has been used by the U.S. army in Iraq and on American warships. Toronto has purchased three devices capable of reaching the 135-decibel range, and one that can emit noise at up to 143 decibels. Health officials suggest noise at up to 85 decibels can cause hearing damage. Protesters have complained that using these devices is too drastic but police have countered that they plan on using the LRADS primarily as a "communication tool" to broadcast messages to large crowds of people. A judge dismissed a motion in June 2010 to ban use of the cannons at the G20 summit in Toronto. The court ruled, however, that police may use the devices only in short bursts to get a crowd's attention, at volumes no more than 111 decibels at a range of no less than 10 metres. The sound cannons were first used to control civilians at the Pittsburgh G20 summit in 2009.

Water cannons

Mounted on trucks, water cannons spray water at high pressure to repel unruly crowds. The devices can typically knock a person off his feet from nearly 100 metres away. In countries including India, Hungary and Israel, crowd control teams have added dye to the water so they can identify protestors later. Police in South Africa have water cannons ready in the event of rioting at the World Cup.

Batons, pepper spray

Officers fire pepper spray and smoke at protesters ahead of the G20 summit in Pittsburgh. (Philip Scott Andrews/Associated Press)Deemed by some to be a less forceful method of crowd control, batons and pepper spray are sometimes used as a means of riot control. Pepper spray, like tear gas, is an irritant and causes runny noses, red eyes and sometimes rashes. Batons are typically wielded against the arms or legs. In 2009 a London police officer struck his baton against a protester's legs, confusing her orange juice container and video camera for weapons. The officer was charged with assault but was later acquitted.