Kettlebells are a really challenging workout and can be used to really improve overall strength and core strength.
I have had some fantastic results with kettlebells and so have all my clients. They are one of my go-to pieces of kit and I love to use them in a lot of my own training.
Kettlebells are extremely versatile and you can move and improve all planes of movement with them.
I advise you start with a light kettlebell (6-8kg), if you have never used one before.