I've ordered one. I found the next one up that has two heads on the end...supposed to improve the error correction of threading, i.e. if I miss with one head I might hit with the other. Only £80. Bargain. It has a tungsten head too as this affects the residual magnetism of the screw which in turn will give the treble a real lift by channeling the the local magnetic field in a more linear fashion down the power lead. Oh, but my mains filter will probably wipe out the benefits...