A kettle bell is a traditional Russian weight made from cast iron that kind of looks like a cannonball with a handle! They might look funny, but kettle bells can yield serious results. They help tone and strengthen muscles while burning fat, and they’re also great for cardio routines and working out your core. Just keep safety in mind: Start out slow with a light weight, until you learn how to use it properly. This means keeping your head aligned with your body, your shoulders back, chest forward and elbows and wrists straight. And don’t drop it on your foot!