Just measure the bone width and pick the clamp that matches we have the 4" Extra Small for tiny bones (6mm), the 6" Small for medium bones (8mm), and the 6" Large for bigger bones like the femur (10mm). Your X-rays will show you which one fits best, or you can check your implant guide for quick sizing. Once you see the bone size, matching it to the right clamp is super straightforward.