CNC machined from a single piece of stainless steel these threaded clamping knobs will last for years and years. They will not break, crack or corrode. They feature an M8 thread for use with anchor dogs and many other dogs, fixtures and accessories associated with the Parf and Multifunction bench systems. Of course they would also be very useful for making your own jigs or work holding devices. Thread size M8 x 8mm long. The thread is M8 x 8mm long, the knob measures 32mm diameter x 12mm deep with gentle knurling for grip. Supplied in pairs.-bg