Ruland knobs are star-shaped to provide a nice grip, making it easy to tighten and loosen as needed. In addition to being easy to tighten and loosen, star knobs are great for confined spaces due to their small dimensions and tool-free operation. Ruland star knobs are available in tapped and stud types with inch and metric threads ranging from #10-32 TPI to 1/2" - 13 TPI or M4 to M16. Knobs are made of shock-resistant technopolymer plastic with zinc-plated steel components and corrosion-resistant stainless steel with stainless steel components. All star knobs from Ruland are RoHS3 compliant.