... 3.Apply to all kinds of medium 4CE.UL.RoHS Universal ultrasonic level meter for distance measurement Ultrasonic levelmeter working principle ... can spread effective in lots of occasion, Such as: storage tank, materials trough, pool, well, Drains, measuring boxes, granaries, silo, etc ... ,15m,20m,30m Material level:3m,5m,7m,10m,15m Universal Ultrasonic level meter\sensor