Take-Home Refill Kit: (4) 1.2 ml syringes 22% Carbamide Peroxide Syringe Daytime use: Wear 60 minutes, once or twice per day. Allow a minimum of one hour between wear time. Do not exceed 60 minutes per application. PRO-SYS® Professional take-home whitening delivers a high-performance system for a more radiant smile. Available in your choice of carbamide or hydrogen peroxide formulas, PRO-SYS® supports a wide range of uses. To eliminate sensitivity, PRO-SYS® contains potassium nitrate and its water-based gel keeps teeth hydrated.