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Its the best and after using it daily the ankle is stronger than before, it the balance that makes you correct certain movements. With Appel or field hockey the feet movement is,quick and small , balance is everything , I recommend it to everyone.

But there is one for the core aswell, you sit in a kinda shell like thing and balance is key.
I have one and it’s killing for the core and abdomen muscles

They seem to be helping you a lot. What does the one for core and abs look like?