Embodiments of the present invention provide an ultrasonic probe having an increased number (e.g., twelve) of ultrasonic sensors for measuring the level of liquid within a sealed container. The ultrasonic probe includes a neck tube that enables the ultrasonic probe to be used with existing, standardized container fittings despite having an enlarged barrel to accommodate the increased number of ultrasonic sensors. Embodiments of the present invention also provide a system and method in which ultrasonic sensors within an ultrasonic probe are activated one at a time to reduce crosstalk between the ultrasonic sensors and their wiring.