I wanted to try these but was not willing to put out as much money as the higher priced options wanted-- these are great! High quality, does what it says, which is a fairly simply concept in that you work out your jaw muscles by squeezing this item between the teeth. You will need strong front teeth, but it's a fine product. Time will tell what the results will be! But as for the product itself it appears to be of good quality, durable and worth the price.