TruSens Aromatherapy Pads for Medium and Large TruSens Ultrasonic Humidifiers | Release calming scents into your home as you humidify the air. Simply add a few drops of essential oil to the aromatherapy pad located in a separate tray on your TruSens Humidifier | Relax to soothing scents of essentials oils in your home while your air becomes humidified | Add a few drops of essential oil to the aromatherapy pad and place in the tray at the back of your TruSens Humidifier | The aromatherapy pads are compatible with the medium and large TruSens Humidifiers models N-200 and N-300 | Use only 100% natural essentials oils | Do not add oil directly to the water in your humidifier | Pack includes 10 aromatherapy pads