The Ultrasone sealing kit uses ultrasonic vibration rather than thermal energy to seal the bags, and this means it is unaffected by moisture, salad or cheese particles in the sealing area. It is extremely reliable and energy efficient, using cold tools that press the tubular bag together for sealing. Very high frequency vibration then literally weld the film together at a molecular level, producing excellent quality seal seams very quickly. The moisture of contamination is literally shaken away.