Custom whitening trays take a patient's smile up to 8.4 shades whiter with virtually no sensitivity* Contains potassium nitrate, which helps decrease sensitivity associated with bleaching. Sticky, viscous gel is mint flavored for patient comfort. To keep teeth their whitest, refill kits should be used for touch-up every 6-12 months. Includes: (6) 1.2ml Syringes (1) Tray Case (1) Shade Guide