There are several types of fire extinguishers and each targets specific elements of the fire triangle, which is made up of heat, oxygen and fuel, according to the Northwest Fire Science Consortium.

Below are each type of fire extinguisher and the classes they fall under.

Water mist extinguishers

Water mist extinguishers are designed to fight Class A fires, and sometimes Class C, says the Fire Equipment Manufacturer’s Association. It discharges a fine spray that removes heat from the fire triangle.

Carbon dioxide extinguishers

These extinguishers are designed for Class B and electrical fires, according to the Fire Risk Assessment Network. They remove both the oxygen and heat elements from the fire triangle. They use liquid CO2 that discharges as a gas and is eco-friendly, says the NACHI.

Halogenated extinguishers

Also known as clean agent fire extinguishers, halogenated agents are rated either ABC or BC, says the Santa Clara Fire Department. They’re often found near computers and electronic equipment. They target the heat element in the fire triangle, according to the Fire Equipment Manufacturers’ Association.

Wet chemical extinguishers

Wet chemical extinguishers are designed to combat Class K fires, specifically those involving deep fat fryers and cooking appliances, says the Santa Clara Fire Department. They discharge a spray, so that grease isn’t splashed around. Wet chemical extinguishers combat fires by targeting the heat element and separating the oxygen and fuel elements of the fire triangle, says the Fire Equipment Manufacturers’ Association.

Dry chemical extinguishers

Dry chemical extinguishers break down into 2 kinds: multipurpose and regular dry chemical, according to the NACHI. Respectively, they handle A, B, C, and B and C fires.

Multipurpose extinguishers take out fires with ammonium phosphate and leave a residue that has to be removed from surfaces. Schools, homes, hospitals, and businesses often use them.

Regular dry chemical use sodium bicarbonate. Unlike multipurpose, they’re not toxic and can be wiped from surfaces easily. They work by separating the fuel from the oxygen element of the fire triangle, according to the Fire Equipment Manufacturers’ Association.

Dry powder extinguishers

Dry powder agents work to create a barrier between the oxygen and fuel elements, according to the Fire Risk Assessment Network. They should not be used in closed-in areas, because the powder is easy and dangerous to inhale. It’s also difficult to clean up afterward.

Dry powder agents should only be used on Class D fires, warns the Fire Equipment Manufacturers’ Association. They don’t work on other types of fires.