Checkweighers are a type of device that weighs an object as it passes through a production line, where it is weighed, classified, transported, accepted or rejected according to predetermined limits. An in motion or tolerance weighing device can do all of this at an extremely high speed. Called high or low speed checkweighers, they are often used to guarantee that filling and packaging machines are producing packed goods at the correct weights. This is not only required by law, but to obtain greater efficiency and lower costs. Inline checkweighers that fit into an assembly line or conveyor system are becoming increasingly popular.