Vaisala RS41 - Manual (Page 39)

Appendix A _____________________________________________ Replacing Radiosonde Batteries
VAISALA_______________________________________________________________________ 37
5. Before placing the new batteries, check the battery polarity
symbols on the radiosonde battery holder carefully. See
Figure 16
on page 37 for an illustration of RS41 battery holder polarity
symbols.
1310-007 Figure 16 RS41 Battery Holder Polarity Symbols
CAUTION Make sure to check the battery polarity symbols in the battery holder
carefully and to place the new batteries correctly. Placing both battery
poles in the wrong direction damages the radiosonde. Placing one
battery pole in the wrong direction prevents the radiosonde from
working.