Thumb nut plum handle nut pentagon nut

 thumb nut is a type of nut that is designed to be tightened or loosened by hand, without the need for tools. It is named after its distinctive feature, a knurled or textured surface that allows for easy gripping and turning using the thumb and fingers.
Thumb nuts typically have a circular or hexagonal shape with internal threads that match the external threads of a bolt or screw. They are commonly used in applications where frequent adjustments or quick assembly/disassembly is required, such as in electronics, machinery, and instrumentation.
The knurled surface of a thumb nut provides improved grip and leverage, enabling easy manual tightening or loosening. This eliminates the need for tools and allows for convenient and rapid adjustments.
Thumb nuts are available in various materials, including metal and plastic, to suit different application requirements. They come in different sizes and thread types to match the corresponding bolts or screws.