Custom Tray Whitening. Whiten your Teeth at home on your own convenience. Trays will be Customized by your Dental Professional. Wear trays daily for time recommended depending on Gel Strength. Gel Strengths include 16%, 22%, 35% CP and 8%, 14% HP. All Gels include potassium nitrate to virtually eliminate tooth sensitivity. Includes: 4 At Home Syringes 3.5ml 2 EVA Sheets for Custom Trays 1 Tray Carrying Case 1 Shade Guide Instructions