Pipelines have to be continuously monitored and checked in order to estimate damage. Uptill now this was done by installing flowmeters inside the pipe. Now, using a technique developed by Rostock University, Germany, it is possible to discover what is going on inside a pipeline from outside. Ultrasonic transducers are clamped onto the pipe wall and ultrasonic waves are then radiated through it. An analysis of how the waves behave provides a precise picture of the state of the pipeline. The new technique also provides mobility- the clamp-on system' can be attached to any pipeline without the need for complicated installation procedures.