ASG1513: Features: -Mouthpiece-Place the mouthpiece in your mouth over the upper teeth. If the mouthpiece is too long, trim the ends back until it fits comfortably. Boil the water. Place the mouthpiece on a spoon and dip in the water for about 8-9 seconds-Mouthpiece moulds for tight and comfortable fit-With ventilation holes to let mouthpiece dry and prevent bacteria growth. Construction: -Solid construction for protection-Construction: Durable plastic. Dimensions: -6" H x 7" W x 7" D, 0.5 lb. Disclaimer: -Warning: Do not leave the mouthpiece if water longer than 9 seconds or the shape will be distorted. Immediately insert into mouth. Close teeth gently to ensure an even bite.