The Apeks submersible pressure gauge, with an internal Bourdon pressuremeasuring mechanism gives you clear information on the gas contents of yourcylinder. The gauge indicates the cylinder bottle pressure and the dial rangeis from zero to 5000 psi (a metric version is also available with a range upto 360 bar). The dial face is designed with clarity in mind by beinguncluttered, with large black figures on a luminous background giving a longphosphorescent effect. This makes viewing as easy as possible, even in poorvisibility conditions.