Features:1. Two mouth trays: One for upper teeth and one for lower teeth2. Great to prevent teeth grinding at night and whiten teeth Description:Item type: Mouth traysMaterial: Food-grade siliconeColor: ClearSize: 7cm X 6cm X 1.3 cmQuantity: 6 Pairs(12Pcs) Package Included:6 x Pairs Mouth TraysUsage Instructions:1.Place the tray into hot water about 70 C for 10-15 seconds to soften and remove from the water.2.Place the trays into your mouth and press the bonding surface of tray and gum.3.Cut the extra at the impressed gum-line and finish making the tray.Notes:1. If the tray is not made well、 you can repeat the process for the second times.2. Please clean the tray with water before using.3. The replacement time of the trays is 3-4 months.4. It is normal to feel discomfort for the first time to wear the tray. You will get used to it after several times.