These are similar in construction to revolution counters. They are used, in particular, for measuring lengths (e.g., on spinning or twisting machines); for counting the movements of a machine (an automatic balance, a pump, the picks of a spinning machine, etc.); or for counting a number of articles (printed sheets delivered by a rotary press, articles carried by a conveyor belt, bank notes, etc.). In practice, the appliances used for these purposes are generally revolution counters which have been adapted to indicate the length or number of units in terms of the revolutions of the driving spindle.