If its what i think it is then supposedly it gives a smoother gearing, seem to remember Zombie saying they did work ( someone said it if it wasnt him). Only thing you need to watch is that it takes up space in the torque drive so increases the torque spring rating a little, think it adds like 10%, so a 1000rpm will act like a 1100rpm, 1500rpm acts like 1650rpm, other than that it works ok i think from what i heard. Dont quote me on that tho.....