The great convenience with this knob is that it instantly converts any standard 5/16" hex-head nut or bolt you supply into a clamp knob. It is particularly handy when you need a knob with a specific stud length to suit an application.
Polypropylene with a textured surface for sure grip, the knob has a hex-shaped recess with grooved walls to hold a nut or bolt head snugly.
Nut and bolt not included. 2" in diameter by 1 1/8" high.