Caltech India offers Gauss Meter. It is best analog field strength indicator or magnetic field strength Indicator. Magnetometer is a pocket size do not require battery.
Magnetometers can be used as metal detector. Gauss meter is generally used to detect magnetism after demagnetizing. It has a scale of positive and negative polarity in small divisions reading in gauss, 10-0-10 or 20-0-20 or 50- 0-50.