Some systems, such as hydraulic actuators and direct-drive electric motors, produce very large forces or torques with short strokes. This means that the actuator may be moved very slightly while delivering its full force or torque . As a result, there is no need to use reduction gear trains to increase the torque it produces and to slow it down to manageable speeds. For this reason, hydraulic actuators can be directly attached to the links, which simplify the design, reduce the weight, cost, and rotating inertia of joints, reduce backlash, increase reliability of the system due to simpler design and fewer parts, and reduce noise. On the other hand, electric motors rotate at high speeds, up to many thousands of revolutions per minute, and must be used in conjunction with reduction gears to increase their torque and decrease their speed, as no one would want a robot arm to be rotating at such high speeds.