Peak hold : 
If the Gauss Meter is without the " Peak hold " function, it is hard to obtain the peak value, Since Gauss Meter's needle will vibrate easily & unsteadily, or the displayed value will be unstable; Using 138A can get the peak value easily with "Peak hold" function.
  Auto accumulating and auto-averaging :
To test the gap's flux density, must test each peak value at the 4 points magnet gap, add & divide by 4 these peak values, to get the average peak value.  Using a conventional Gauss Meter must record down the 4 tested peak values, & compute the average peak value manually, this is inconvenient & time-consuming. 138A is an unique design with "4 times auto accumulating & averaging" functions, rapid test & accurate result.
  2 thickness of probe's sensor for selecting : 
A.  0.5mm ± 0.05 mm ;     B.  0.6mm ± 0.05 mmTwo Ranges : 0 ~ 2.0K ,  2.0K ~ 20.0K gauss.

Normal : ± ( 0.1 % Rdg.+ 0.05% FS )
Peak hold : ± ( 0.2 % Rdg.+ 0.1% FS )
( 1 / 4 )×4 : ± ( 0.3 % Rdg.+ 0.1% FS )
Digital Display : 3 ½ digits, Resolution : 1 gauss.
Measuring Range : 0 ~ 20K gauss, autoranging.
Accuracy ( probe excluded ):
Peak hold decay < - 0.05 % / sec.
Accuracy ( probe included ) :
At 10KGS : ± 1.7 %
0 ~ 15KGS : ± ( 2 % Rdg. + 0.1% FS )
15 ~ 20KGS : ± 2.5 %



     6.     Dim. : 14 ( L ) × 22.5 ( H ) × 23 ( D ) cm.
     7.     Net Weight : 2.8 KGS.