Thumb Screws are small discrete male and female handwheels. Our thumbscrews are round in design with a small ridged thumbscrew head for grip and adjustment. Our thumbscrew heads are all 15mm in diameter with either a male or female thread. Our thumbscrew thread sizes range from M4 , M5 up to M6. These small discrete and extremely useful grip knobs are suitable for a variety of applications where small adjustment handles are required.