The Model GM2 Measures the strength and polarity of magnetic field up to 30kG when using a standard probes, or 800 gauss (resolution 0.01 gauss) if an HS probe is used. Functions include DC, AC and peak hold along with a user-adjustable alarm which has three modes of operation. DC background field can be subtracted out either by pressing Relative Zero or by manually adjusting the offset. The meter includes battery, AC adapter analog output jack and calibration certificate. If a standard probe is used, resolution is 0.1 gauss up to 19,999.9 gauss, which is stronger than the field of any permanent magnet. This digit display allows measurement of tiny difference in strong fields. Above 20kG the meter auto ranges to a 30kG range. Interchangeable probes are available at two sensitivity levels: standard to 30k gauss and HS (resolution 0.01 gauss); these are available in universal (bendable), axial and transverse shape. Choice of one probe is included with the meter.