The residential elevators are of lower cost and simple design than commercial elevators. They might have different design characteristics suited for home furnishings and interiors. Residential passenger elevators might have designed wooden shaft-access doors rather than the typical metal doors of commercial elevators. Construction may be less robust than in commercial designs with shorter maintenance periods. But safety systems such as locks on landing doors, over speed governor, and emergency talk must still be present in case of an emergency. Home lift or residential elevator is the elevator which is meant to serve only a private family.