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. For FeelFree Kayaks, 3 Water Kayaks, and Jonny Boats you will need an adapter to be compatible. We offer the needed adapter in a single pack (AAP-1012) and a six pack (AAP-1012-6).