Cast Iron vs. Competition Kettlebells - What’s the Difference? Competition kettlebells have the same standard dimensions, regardless of weight. The dimensions of cast iron kettlebells get bigger as the weight gets heavier (bell, window, and handle). You might choose a competition kettlebell – also known as a Sport style kettlebell – if you’re practicing a specific skill that requires a lot of technical nuance, such as Turkish Get Ups or Kettlebell Sport lifts. Most competition kettlebells are ho