I WAS SO EXCITED TO TRY THIS PRODUCT. I FOLLOWED THE DIRECTIONS, AND AFTER TRYING TWO TIMES TO GET THE TRAYS TO FORM TO MY TEETH, IT DIDN'T HAPPEN. WHAT DID HAPPEN WAS MY JAWS ACHED SO BADLY, I HAD TO TAKE THE TRAYS OUT. THE TRAYS NEVER CHANGED THEIR SHAPE, BUT REMAINED EXACTLY AS THEY WERE--HARD AND UNWIELDING. THE BLEACH MAY BE VERY GOOD BUT I'LL NEVER KNOW BECAUSE THERE IS NO WAY THOSE TRAYS ARE GOING BACK IN MY MOUTH .