They are made of zinc alloy, chrome plated, good weight and feel to replace your plastic knobs.
Fits 6mm pot shaft.
Material: Chrome Plated, Zinc Alloy
Size:25 x 14mm/0.98 x 0.55"(Dia x H)
Diameter of axle:5mm/0.2"
*****NEVER pinch the control shaft with pliers to make a knob fit. This can cause the split shaft to break. *These are factory parts. Instructions are not included. If you have any doubt about installation, consult your local luthier.