The Smackdown Mounting Hardware Knobs give anglers a dependable and clean solution for securing accessories to track systems and rod holder mounts. Available in 1/4 in. and 5/16 in. options, these black-finished knobs provide a snug, vibration-resistant fit that keeps hardware tight even in rough water. The 1/4 in. version fits 1/4-20 T-bolts only, while the 5/16 in. version fits 5/16 T-bolts only, ensuring precise compatibility with your Smackdown or similar boat mounting setups. Built for quick installation and reliable performance, these knobs enable you to make fine adjustments on your boat quickly and frustration-free.Available in 1/4 in. or 5/16 in. size options1/4 in. fits 1/4-20 T-bolts only5/16 in. fits 5/16 T-bolts onlyBlack finish resists corrosion and provides a clean lookSecure, easy-to-grip design for quick hardware tightening