Radarcan R-101 User Manual page 12

Can I wear the PORTABLE MOSQUITO REPELLER in water?
No. The mechanism could be damaged.
The mosquitos won't go away!
Mosquitos might be observed in the surrounding area;
however those would be male mosquitos, as only female
mosquitos bite to feed on blood.
My PORTABLE MOSQUITO REPELLER doesn't work.
1. Be sure that the battery is new and correctly inserted.
2. Check that the on/off switch is to the left and that the
"ON" sign is visible. Putting the PORTABLE MOSQUITO
REPELLER close to your ear, you will hear a faint hum.
3. Do not block the PORTABLE MOSQUITO REPELLER
sound outlet.
Once you have taken the information above into account,
if you still do not hear the faint hum from the PORTABLE
MOSQUITO REPELLER, get in contact with the RADARCAN®
technical department.