A more thorough explanation:

A dog sniff inspection is when trained dogs are used to identify suspicious objects by detecting smells. This can be helpful in investigations because dogs have a better sense of smell than humans. Whether a dog sniff inspection is considered a search or seizure under the Fourth Amendment depends on whether there is a reasonable expectation of privacy being intruded upon.

• Inspecting containers, packages, lockers, or vehicle exteriors with a dog sniff inspection is considered legal without a warrant or probable cause, as long as the dog is lawfully present and the conduct is proper.
• However, a dog sniff inspection of someone's home is considered a Fourth Amendment search because people expect their homes to be free from government intrusion.

These examples illustrate how a dog sniff inspection can be used in different situations and how the legality of the inspection depends on the location and circumstances.