Integrated Geo Instruments and Services [P] Ltd. [IGIS] manufactures signal-stacking resistivity meter. Such a marvelous signal-stacking resistivity meter is the model SSR MP L. It is a high quality microprocessor-based data acquisition system, including multiple groundbreaking features. The instrument-design incorporates several advanced techniques of digital circuitry to make signal-stacking resistivity meter a reliable geophysical tool, that delivers high quality data, useful for all types of mineral and groundwater, geo engineering and environmental studies. This signal-stacking resistivity meter functions on a constant current mode with three settings 1, 10 and 100 mA. The SSR MP L has output voltages of up to 400 V along with power output just up to 40 W. The improved model of the instrument achieves excellent depth penetration with relatively low power transmission. The signal-stacking resistivity meter, effectively uses signal-stacking up to 16 successive readings to obtain the beneficial signal enhancement. In the presence of random [non coherent] earth noises, the signal to noise ratio of the SSR- MP L measurement will be raised by vN , while N is the number of individual readings. Hence, the meter can be used for depths of up to 500 m under favourable geological conditions. A signal-stacking resistivity meter can also used as spot logger.