The Now Whitening system enables super efficient teeth whitening without the time and expense of making individual custom trays. The trays have been designed to flex without distorting and the multiple finger grips on the inside surface of the trays holds them comfortably in place against your teeth. these reusable upper and lower trays fit most mouths. The uniquely designed and patented trays are made from medical grade silicone and are ribbed to allow flexing with minimal distortion. The trays remain comfortably in place and ensure the Now gel is in close contact with the patient?s teeth.