IQOS USA Heets Marlboro Heatsticks. Heatstick is designed for IQOS DUO device. Heatsticks have 12 flavor options, including Rich Regular, Regular, Balanced Regular, Smooth Regular, Black Menthol, Menthol, Mint, Purple Menthol, Yellow Menthol, Fusion Menthol, Bright Menthol. Diverse choices of flavors available regular original, pure menthol and fruit menthol.