This is yet another gravity key design, quite a simple one, whilst experimenting with the other gravity keys I found they would work quite well with the weight directly over the tension spring and no other weight in the arm, just the weight supplying the kinetic energy to make the key feel right, I had a few spare parts left over from previous keys so decided to try the idea out, it does work quite well, it took a bit of time getting the right spring and it was a bit difficult building the isolated contact as that also had to house the tension spring and adjuster,  a real little fun key  :))