Hydraulic elevators are used frequently and have a vast range of applications. Small buildings under G + 3 floors are typically where hydraulic units are found. Hydraulic units are limited by the number of floors that they can serve. Often these limitations are not due to the inability of the equipment, but reflect more on the cost of installation versus the long-term maintenance costs. Hydraulic elevators, which serve many floors in high traffic facilities, are not as cost efficient as are traction units, in regard to the units' performance and maintenance cost.