This is another very experimental key design, it has a sliding counter weight  which  alters the centre of gravity and also there is a soft coil spring to change the tension of the key when the weight has been set to the best "feel" position for the operator, the changes are very subtle, again I've used adjustable bearing mounts so the bearings position can be set to the optimum in relation to the main arm. The top picture is now the finished key, the lower picture was the first prototype, it had a few constructional problems so I used most of the parts to make this modified version which has a better finish but still retains the nice feel to the action.. Just needs to be polished up and another key to the G3YUH collection :()