The YakAttack ScrewBall™ is a 1″ ball mount that is 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).. Featuring a rubber washer on the underside to allow compression and help keep the Screwball locked in place while in the track. Designed for harsh marine environments and made in the USA.