Ball Link Swivel Joint Brass and Nylon with Screws & Nuts Description Single End Ball Swivel Joint. Each pack contains 2 pieces These Ball Swivel joints are ideal for connection on helicopter swash plates and all staggered surfaces. Tough nylon extender 20mm long with hole in each end self tap 2mm thread. Brass Ball with 2mm clearance hole through. Supplied with screws & nuts.