I got this as I'd never seen anything like it before and my jaw is not an area I have thought of exercising before. It arrived quickly and in a product box along with some easy to follow directions.
Moving this device with your fingers seems easy so I was sceptical as to whether it would do anything. Well might be easy to squash with your fingers but with your teeth is a completely different matter! I am now 4 days in and can now do 12 bite down and release before my jaw aches which is an increase on the 5 I managed the first day! The device is still as rigid as it was when it arrived so I can only summise that my jaw is indeed getting stronger.
I would recommend this to anyone asking.