Introducing the 1/4 inch x 20 tpi T-Track Knob, Hex Head Bolt and Washer Set by POWERTEC. These through-hole knobs and hex head bolts are commonly used with mini slot tracks, but the 1-1/ 2" long bolts can accommodate a wide range of thick stock (including 1/2" and 3 /4") to secure and/ or attach most assemblies. This through-hole knob eliminates the challenge of finding the right bolt length, and makes using the knobs with your woodworking projects quick and easy to set up. //VERSATILE: The through-hole knobs and bolts are the perfect replacement for lost or damaged knobs and bolts for all these accessories and more. This knob and bolt set can serve as high-quality replacements that last for years, and they are the perfect solution for replacing damaged or lost knobs and bolts for all these accessories and more. They fit many different types of t-slot tracks, including hex head bolts and t-style bolts, as well as high-end Anodized Mini T-Track, which has no play and smooth adjustment, and holds better than universal or double cut tracks. //Commonly Used Applications: Router bit guards, stop blocks, flip stops, fence feather boards, tabletop feather boards, router table fences, router table tracks, miter gauge fences and more can use knobs and bolts with a 1/4 x 20 TPI thread. Material: Multi-Surface.