Specifications: Item Type: Teeth Whitening Mouth Trays, Materials: Thermoplastic copolymer, Color: Clear, Quantity: 2 Pc, Size: 6.3cm x 5cm. Submerge the mouth trays into hot water for 5 seconds, remove and let cool for 10 seconds. Place the trays on your teeth to form an impression, trim at the gum-line, and apply whitening gel to whiten your teeth.