These are nylon, shatterproof star knobs with female threaded brass inserts. They make a great addition to home-built jigs and fixtures or a replacement for a standard or broken knob on machinery. The through tread allows use anywhere regardless of the bolt length. The metric thread brass insert guarantees smooth clamping in all situations. The 40mm diameter, 7-lobe design makes tightening and releasing easy. These knobs are resistant to solvents, coolants, oils etc. Supplied in pairs, available with M6, M8 or M10 thread.