An assortment of round-head screw knobs from The Hillman Group. Screw knobs, or clamping knobs, are basic components that provide a strong grip or secure control through the use of elements such as texturing, knurling, lobes, or wings. These knobs are ideal for applications that require quick hand adjustments. Variants included in this assortment are engineered to fit socket cap screws ranging from #4 to 5/16" in diameter. Full assortments of #59199 contain twelve (12) refills comprised of Hillman item numbers #59200 - #59211.