The direction dependence of the count rates measured by ZP1210 and ZP1200 type GM tubes in the REXUS-17 REM-RED experiment. The uncertainties of the measured data estimated from 5 s integration time are indicated in the ZP1210 curves above 15 km with vertical error bars. Only this region was used to draw conclusions about the directionality of the cosmic radiation flux. The dashed line indicates the 15 km altitude; above this altitude the uncertainties of the ZP1210 values are 4–5%. Note that for the data evaluation the duplicated ZP1210 GM tubes were used with duplicated sensitive volume normalized to the sensitive volume of one single tube in order to have better comparison with the BEXUS GM profiles in Figure 5.