Mentor-Aluminium-Turning-Knobs-with-Setscrew-Fixing-Mentor-508-61-p-This-aluminium-turning-knob-from-Mentor-has-been-manufactured-for-professional-equipment-and-comes-with-setscrew-fixing-Stylishly-designed-with-a-black-anodised-finish-p-Mentor-508-61-Aluminium-Turning-Knob-Setscrew-24mm-Silver-Without-Indicator