Select your desired Hitch Ball size above. Our Hitch Balls are custom-made for our Ball Mount locking system to ensure the ball stays securely in place within your trailer's coupler. This prevents any spinning and guarantees a safe and snug fit. All Hitch Balls come with a 1-1/4" diameter shank. Each Trailer Dolly package includes: Scout 3K: 1 7/8" and 2" (custom) Force 5K & 10K: 2" and 2 5/16" (custom) Transformer 15K: 2" and 2 5/16" (custom) These hitch balls are NOT compatible with: Carrier 13K trailer dollies – Please contact us to purchase standard hitch balls. Trailer dollies purchased before June 11th, 2021 – you will need to purchase a new Ball Mount kit, as we no longer support the old 1" diameter shank size. Please Contact Us for details. If you need an extra Hitch Ball, we have a wide range of sizes available: 1 7/8" 2" 2 5/16" 50mm - this size features custom weld spots