The Micro-g LaCoste gPhone gravity meter uses the Zero-Length Spring™ sensor technology to provide microGal repeatedly with vey low static drift which makes it the best suited as a monitoring meter. Whether you are interested in earthquake or volcanic studies, earth tide or reservoir monitoring, the gPhone will out perform all others. The gPhone can also be used as an ultra sensitive low frequency seismometer for these areas of studies. The gPhoneX gravity meter is based upon the LaCoste and Romberg technology that has dominated land gravity meters since 1939. The gPhoneX gravity meter has a low drift so that it can be used to integrate periodic signals (like earth tides) for very long time periods (years). The gPhoneX also has excellent high frequency response so that they can be used to monitor higher frequency non-periodic events such as earthquakes. The gPhoneX can be coarse-ranged over 7000milliGals (worldwide), and has a ±50 milliGal dynamic range during measurement.The versatile gPhoneX gravity meter has a sophisticated data acquisition system (Micro-g LaCoste's gMonitor software) synchronized by a rubidium clock that can be locked to GPS so that arrays of gPhoneXs can be used to give a wider area picture of seismic or long period gravity changes due to subsurface density changes. The instrument can be monitored and controlled via the internet for remote operation.The principle behind Micro-g LaCoste's gPhoneX is the patented LaCoste & Romberg zero-length spring suspension system. The gPhoneX is based upon the G-Meter, but with significant upgrades: It has an improved thermal system - a double-oven - for more precise temperature stability. The instrument also has a true vacuum seal so that it is completely insensitive to buoyancy changes due to atmospheric changes. It employs the Aliod beam nulling system for precise digital measurement of gravity with 0.1 microGal resolution.