Waiting rooms may be staffed or unstaffed. In waiting rooms that are staffed, a receptionist or administrative staffer sits behind a desk or counter to greet customers/clients, give them information about the expected waiting period, and answer any questions about their appointment time or the appointment process. In doctors' or dentists' waiting rooms, the patients may be able to make additional appointments, pay for appointments, or deal with other administrative tasks with the receptionist or administrator. In police stations, check cashing stores and some government waiting rooms, the receptionist or administrator is behind a plexiglass barrier, with either small holes to permit communication, or, in higher-security settings, a microphone and speaker. In reception areas with a plexiglass barrier, there may be a heavy-duty drawer to enable the client to provide money or papers to the receptionist and for the receptionist to provide documents to the client. The plexiglass barrier and the drawer system help to protect the receptionists from aggressive or potentially violent clients.