Ok yes its another "Fun" key, I must admit I do like fun keys as long as they perform well, to many Amateur home brew keys built from scrap have a pretty scrappy performance, for some time I've wanted to build a single bearing key ie the arm suspended from one bearing, this is quite difficult mainly as the bearing itself must have certain properties not normally found in a bearing, such as no end play and very free movement, I found this particular bearing at a Radio Rally, I think it was out of a large stepper motor, and it suits this purpose very well, in fact it is really two bearings in one which is a bit of a cheat but who cares its a fun key :() I've used some 8mm nuts and bolts to form the contact post with two magnets in repulsion mode for the tensioner and its turned out an ace little key with a fast lightweight action, a real Amateurs key :))