Konova Nitsan Flywheel with K7 150cm Slider (Include Slider) By adding the weight, you get much better motion control, it makes sliding the camera along the track much easier and smoother. The design is very simple, it fits right on and secures in no time at all. and then you just need to add a weight on. Previously you would have to use one hand on the carriage device to push the camera along the track, now with this improvement in the motion you only need to push the camera. it allows you to keep both hands on the camera controlling focus and camera operation. This new feature makes the motion easy and almost automatic. Now you can concentrate completely on your shot.