You can have white bright teeth in only 5 days 30 minutes a day using the one size fits all dental trays pre-filled with just the right amount of whitening gel.Clinically proven to whiten your teeth up to 7 shades whiter (average 4 shades). There is no messy mixing or filling of the trays as they are pre-filled and they whiten the front and back of the teeth. This is important as Teeth are translucent and stains on the back can show through the front