The YakAttack ScrewBall is a 1″ ball mount that is compatible with YakAttack MightyMounts, 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.Track mounted 1″ ballLifetime warrantyMightyBolt mount compatible with most kayak track systemsMade in the USA