A dip stick is essentially a stick or rod that is calibrated to indicate level. The dip stick is lowered vertically into a tank or vessel until it reaches a reference point. Usually the bottom of the tank is used to ensure that the dip stick is inserted to the correct depth. The dip stick is then withdrawn and the level is ready by determining where the interface last made contact with the dip stick. Reading the scale on the dip stick indicates the level measurement. A lead line acts in the same way as a dip stick. A steel measuring tape with a weight attached, the lead line can be used in most places that the dip stick can. Since the lead line can be rolled up into a smaller, compact unit, it is often easier to handle than a dip stick.