A bar mat, also know as a spill mat, can be seen at just about any bar you go to. Many bar mats are used for marketing by having the name of a particular alcohol on them.
Bar mats are typically made of thick rubber with rubber bristles that hold glasses in place when lined up on the mat.
The main purpose of a bar mat is to hold wet glasses, help to prevent spilling and to protect the bar surface. They also cut down on cleaning time by keeping spills contained in the mat itself and not the bar and floor. They are easy to lift up and empty liquid into the sink.
There are two kinds of bar mats. One is used right in front of the bartender to mix drinks. The other is typically a little wider so the bartender can put drinks on the mat of the service area, which is where the waiter/waitress picks up drinks for the table customers. Bar mats can also be custom made.