ThermoForm Tray Bleaching Systems provide the same efficacy of professional systems without the expense of the lab-created dental trays. ThermoForm bleaching trays promote uniform whitening of the teeth and usually contain active ingredient of 10% - 22% Carbamide Peroxide.  ThermoForm kits found in OTC markets usually contain inferior bleaching trays and a very small or undisclosed percentage of active ingredient. Sometimes these OTC kits do not contain any effective active ingredient. Be sure the labeling clearly identifies the type and percentage of active ingredient and be sure to examine the thermoform bleaching tray so that it provides low heat molding, full coverage area and a soft comfortable fit.