The main advantage of hydraulic elevators is that, using the force of gravity only, the car can be lowered to the nearest landing in case of a blackout. SImple to maintain and with reduced installation time hydraulic elevators are a cost effective alternative. For hydraulic elevators the power unit can be positioned in a more distant location. This feature becomes a more evident advantage in case of installation in existing builgings. It is possible hydraulic elevators to be operated Machine Room Less (MRL) - in metal cabinet. The absence of counterweights is a way to save space in each floor.