The Flowcine Serene is a two axis spring arm that attaches at the end of the (2.5/3) arm. It stabilizes vibrations and motion errors on the vertical axis that comes from walking or running with the rig. It also stabilizes side to side errors in the same scenarios by counter pivoting around its centre axis. At the same time you have full use of the spring extension that will allow you to go from high to low mode while at the same time the Serene will take care of the vertical and side to side stabilization adding two more stabilized axis to your existing system. The Serene can take rigs between 6-20 kg and you can easily fine tune the spring tension without tool. Of course it works great with the Gravity One, but it also works really good for other gimbal rigs like the Freefly M"vi, B-steady or most other gimbal rigs. The Serene mounts at the very end of the arm and the string is routed upwards and through the Serene instead of the normal way straight down from the tip of the Easyrig. To make this happen you have to slightly alter your arm with one or two holes (depending on model). This is a fairly easy operation that most can do themselves and a drill template piece is supplied for exact placement of the holes.