Introducing the 5-Star Thru Knob and Hex Bolt (4 kits) Set by POWERTEC. These multi-functional knobs provide you with reliable fastening option for an assortment of t-track systems, jig fixtures and general purpose clamping projects - or any application that accepts the standard 1/4-inch bolt heads. The user friendly 5-star design allows you to utilize a secure hand-grip while maximizing your adjustment and tightening control. Whether you're a woodworker or DIY enthusiast, you'll find that they streamline your workflow, while enhancing your project results with a simple twist and turn motion. The black knob is made with high quality, durable polymer plastic and flaunts a matte black finish. The easy to grip design comes with ample finger gripping space, and is comfortable to twist and secure with the hand. The knobs are 2-1/4" in diameter and have a 1/4-20 hole thru threaded insert to accommodate the included 3" bolts. Material: Multi Pack.