The carriage is driven by an external linear belt that can be adjusted to reduce lash and is driven along the external roller bearings. The pulleys have maintenance-free ball bearings. Belt tension can be readjusted by a simple screw adjustment device in the carriage.
The ELFZ is a carriage driven actuator with single fixed belt. Beacuase the single belt wraps around with both ends and is fixed to the carriage, a larger capacity can be realized.