The benefits of using kettlebells are seemingly endless. That’s why many coaches and kettlebell devotees refer to the equipment as the “Swiss army knife” of fitness, said Jahkeen Washington, owner and founder of the Harlem Kettlebell Club. With just one piece of gear, you can train to increase both strength and cardiovascular fitness.A quality kettlebell should be a one-time investment. Employing various swings, squats, and curls, we tested 16 top-rated kettlebells to determine that the Rep Fitness Kettlebell is the best option for all types of at-home workouts.