Features 1. Made of food-grade silicone, safe, no toxin side effect, safe for using it. 2. EVA thermoplastic material, high transparency, better to fit. 3. The mouth trays can be formed repeatly. 4. Great to prevent teeth grinding at night and whiten teeth. Specifications Material: EVA Size: Approx.6.5x5cm Color: Clear Package included: 1pcs / 2pcs * mouth guard(we recommend that you buy 2 pcs for both the upper teeth and the lower teeth. ) HOW TO USE IT? 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. The tray is now moulded 3.Cut the extra at the impressed gum-line and finish making the tray