The total range of scientifically useful vacuums extends from approx. 1000 mbar (atmospheric pressure) down to 10-12 mbar – the ultra-high vacuum range. A physical measurement of the whole vacuum/pressure range is not necessary. Particular sensors and gauges must be used for parts of the whole range – rough, high and ultra-high vacuum. These systems are also offered in combination as multi-range vacuum gauges for covering multiple measuring ranges.