Not all fires are the same and not all fire extinguishers are equal. Knowing the differences can help determine which extinguisher to purchase for your home or vehicle.

Step 1: A is for Ash. Class A fire extinguishers are designed for extinguishing combustible materials that leave ash, such as wood, paper and plastic. An APW extinguisher is filled with pressurized water and should never be used for grease or electrical fires. Class A extinguishers are marked with a green triangle.

Step 2: B is for Bubbles. Class B fire extinguishers should be used to extinguish flammable liquids such as grease, gas or oil. Liquids have a boiling point, ergo they can make bubbles. Class B extinguishers are marked with a red square.

Step 3: C is for Current. Class C fire extinguishers are for fires caused by electrical currents. Extinguishers receive the C rating when their chemical agents are non-combustible. Class C extinguishers are marked with a blue circle.

Step 4: D is for Ductile. Don’t worry too much about remembering that one. Class D fire extinguishers are for use with combustible metals such as magnesium, titanium and sodium. These types of fires typically occur in laboratory settings. Class D extinguishers are marked with a yellow decagon or star.

Step 5: K is for Kitchen. Class K fire extinguishers, similar to Class B extinguishers, are designed specifically for small grease and oil fires that often occur in kitchens and automobiles. Class K extinguishers are marked with a black hexagon.

Step 6: Both BC and ABC extinguishers leave a sticky residue that helps to prevent re-ignition of fires. The residue is corrosive and should be cleaned up once the chance of re-ignition has passed.

Step 7: BC extinguishers are often filled with carbon dioxide. These extinguishers do not leave any residue, but are not recommended for Class A fires.

Step 8: The numbers associated with each letter on an extinguisher indicates its ability to extinguish fires. The larger the number the more extinguishing power it has. The numeric rating on Class B extinguishers indicates the approximate number of square feet of fire it can extinguish.

Step 9: Choose a 10-pound extinguisher for areas such as garages and shops, where fires may grow large before being noticed. Choose a 5-pound extinguisher for kitchens and a 2-pound extinguisher for cars, where the smaller size may be advantageous for extinguisher placement.