The extremely militaristic police response to the protests in Ferguson, Missouri, which have occurred nightly since a police officer shot unarmed teenager Michael Brown to death on August 9, has shocked many Americans.

In its tactics, appearance, and especially equipment, the security operation looks more like it belongs on a battlefield in Iraq or Afghanistan than in the streets of an American suburb. Armored vehicles, tear gas, full combat gear, rifles — what is all that?

From LRADs to MRAPs, here's a brief guide to the equipment being used against civilians in the St. Louis suburb.

LRADs are sound weapons so piercing they cause physical pain

Warning: do not click this video with the volume on your computer turned up. You will regret it.

The LRAD, or Long Range Acoustic Device, is basically a sound cannon: it has the ability to send loud, targeted bursts of sound designed to disperse military targets, pirates, and crowds. They are not just noisy. The sound they emit is powerful enough to cause severe physical pain and headaches to those in range. According to an executive at the firm that manufactures LRADs, the devices can also cause permanent hearing loss if used in anything more than short bursts.

Police appeared to use LRADs to disperse the Ferguson protesters on Sunday, August 17, and Wednesday, August 13. Video of their use on Sunday, part of which is embedded above, appeared to show them in continuous use for several minutes. LRADs look like large satellite dishes and are typically mounted on top of trucks. The police-grade model in apparent use in Ferguson emits sound at up to an ear-shattering 149 decibels, well above the 130-decibel threshold for hearing loss.

In the short video linked above, you can hear the LRADs and see them mounted on the armored trucks in the background of the shot.

Disgraceful. MRAP mounted LRAD = Afghanistan-grade gear MT @PDPJ #Ferguson: high powered rifles trained on protesters pic.twitter.com/BtE5ivGMtI — Thomas Chappelow (@tomchappelow) August 14, 2014

MRAPs are armored vehicles originally built for military use in war zones

Mine Resistant Ambush Protected Vehicles, or MRAPs, are heavily armored trucks designed to withstand the detonation of land mines or IEDs. They were first deployed by the US military in 2007, designed specifically for use in Iraq, where al-Qaeda and Iranian-backed Shia militias were using highly developed IEDs. Now the vehicles are being passed down to police departments.



Asked why MRAPS were being used in Ferguson, a place with neither land mines nor IEDs, Ferguson police chief Tom Jackson replied that "people are using bombs now." However, there have been no reports of bombs being used in Ferguson — he may have been making an existential point about bombs being items that exist in the world.

While MRAPs certainly look tank-like, particularly when rolling down a suburban America street, they are not in fact tanks because they drive on wheels rather than treads and lack a cannon.

The police are wearing more body armor than actual soldiers use when patrolling in war zones

The gentleman on the left has more personal body armor and weaponry than I did while invading Iraq. pic.twitter.com/5u6TxyIbkk — Brandon Friedman (@BFriedmanDC) August 14, 2014

The officers on the streets in Ferguson have deployed wearing body armor, including gas masks and visors, prompting a number of military veterans to point out that the police are wearing more protective gear to confront protesters than actual soldiers typically wear while on patrol in active war zones.

Former Seattle police chief Norman Stamper warned that when police dress in military uniforms, they contribute to an atmosphere of hostility that can actually escalate the risk of violence, rather than suppress it.

"Keeping the peace at a demonstration essentially means having police officers in standard everyday uniforms, not military garb," Stamper said. Otherwise, they can come to "view the community as the enemy. In the process they become an occupational force where they are in charge — in the name of control, in the name of public safety, taking actions that actually undermine legitimate control."

The cops are carrying rifles based on the military M4 Carbine

The police in Ferguson are armed with rifles, which former Marine Paul Szoldra described in Business Insider as "short-barreled 5.56 mm rifles based on the military M4 Carbine." Numerous reports from Ferguson indicate that the rifles are frequently pointed at people who pose no immediate threat, as a way to intimidate civilians into compliance with police orders.

It appears that the rifles are loaded with rubber and wooden bullets, which are less lethal than standard ammunition, but can still cause severe injury. Moreover, protesters who find themselves in rifle sights may not have an opportunity to verify what kind of bullets they contain, making the rifles just as intimidating to citizens as they would be if they contained "real" ammunition.

The use of the rifles prompted further criticism from military veterans, who pointed out that the police were using them in a way that was likely to aggravate hostilities, rather than calming the situation.

A few people have pointed it out, but our ROE regarding who we could point weapons at in Afghanistan was more restrictive than cops in MO. — jeffclement (@jeffclement) August 14, 2014

Postures tell story of perceived threat. L: aggressive security during AJ camera dismantling. R: patrolling in Iraq. pic.twitter.com/b3q7cyPvG4 — Alex Horton (@AlexHortonTX) August 14, 2014

Tear gas is a chemical weapon that's banned in combat, but is being used on the streets of a Missouri suburb

Police have used tear gas to disperse protesters on several nights of the Ferguson demonstrations. On the evening of Sunday, August 17, an eight-year-old boy was left gasping for breath after gas hit the group of protesters where he was standing.

Tear gas is a chemical mist or gas that irritates the mucous membranes in the eyes, nose, mouth, and lungs. In addition to tears, it can cause coughing or choking if inhaled, as well as severe pain. Although in most cases it merely causes temporary symptoms, it can have more serious effects, including asthma attacks, eye damage, and chemical burns.

The gas is often fired from cartridges or shells, which can also be dangerous projectiles themselves, causing bruising, broken bones, and even death.

The 1993 Chemical Weapons Convention, to which the US is a party, prohibits the use of tear gas in combat. However, that treaty contains an exception for "law enforcement including domestic riot control purposes," which allows tear gas to be used by police officers in situations like the Ferguson protests.

That means that using the gas in Ferguson doesn't necessarily break the law, but the U.S. army would be violating a treaty if it used the same tactics in Afghanistan.