Many Hunter wheel balancers have a "double thread quick take up" thread design that is difficult to match. A normal thread starts at only one spot on the shaft. Double threads start at 2 spots 180 deg. from each other. The wingnut for Hunter double thread shafts has 8mm thread spacing and the shaft has 4mm spacing but it is actually 2 sets of 8mm spaced threads 180 degrees out of phase. This allows the the wing nut to start threading in 2 possible positions instead of just one. Thread spacing is the distance of one thread and one space; for example, the distance from the left edge of a thread to the left edge of the next thread. If you have a Hunter Wheel Balancer with a 40mm shaft and 4mm thread spacing, you have a 40mm X 8mm Double Thread Shaft. FITS THE FOLLOWING HUNTER WHEEL BALANCER MODELS: DSP7700, DSP8500, DSP9000, DSP9200, DSP9500, DSP9600 GSP9700. OEM / Aftermarket Interchange Part Numbers: Haweka: HW124-408-005, 124-408-005, Hunter: 76-432-1, 76-438-2