Includes four of each: Convertible Knobs, 1-1/2” MightyBolts, Track Nuts, 1-1/4” Socket Head Cap Screws. All standard 1/4-20 thread. Compatible with YakAttack MightyMount’s, GearTrac, and most other kayak track systems from Scotty Fishing Products, RAM Mounts, and YakGear.