Almost every state and city has a K-9 unit. But if you're like me, you're not sure what exactly they are and how they work. Well, there are many different types of K9 units, such as patrol dogs, narcotics dogs, arson detection dogs, and explosives detection dogs. Additionally, K-9 units feature two helpful new pieces of technology to help protect canine partners. Patrol dogs are trained to protect their partner. The dog is trained to bite in two circumstances. The first is when the officer orders the dog to attack. And the other is when an aggressive move is made towards the officer that the dog will attack. A patrol dog is also capable of tracking and following a person. Smells that are several hours old may follow. They are not fooled by false tracks or if other animals cross the trail. Dog breeds used for patrol are German Shepherds, Rottweilers and in some places Dobermans. Narcotics dogs are not like patrol dogs. They are not aggressive or trained to attack. There they were carefully chosen for their character. They must be patient and willing to work for long periods of time. They have extremely high levels of drive and enjoy working. The dogs are trained to detect marijuana, hashish, cocaine, crack, heroin and methamphetamine. Dogs are trained to look for narcotic odors in all different areas. Such as vehicles, luggage, warehouses, buildings and open areas. The dog breeds used in drug trafficking are Labradors, Golden Retrievers, German Shepherds and millions of Belgian dogs. Fire dogs are proving to be a valuable resource for arson investigators. Fire dogs are used more and more every year by investigators and private companies. Who investigates for insurance companies. The use of a dog is to help locate where the fire started and what caused it. The dog reduces the number of samples that need to be collected and sent for testing. This saves time and money. Dogs are trained to detect a variety of chemicals used in a fire. Such as gas, lighter fluid, started coal, diesel. Kerosene, alcohol, brake fluid, paint thinner and much more.