Yes, the mosquito coils.
I was first introduced to them while living at Ping Yang Wu Shu School and being eaten alive by mosquitos at night. Once I made my distress known, a quick trip to the local store solved the problem and introduced me to the wonders of these coils that burn like incense and really do keep the mosquitos away. There must be something especially tasty in my blood because others around me were not bitten by mosquitos.
Here in Japan I have been using them for ten years ever since and they are lifesavers, as the bulk of my training is outdoors these days, either next to my house or in a large park. I realize that a True Warrior should be impervious to such minor unpleasantries as nagging mosquito bites, but let's face it, I would rather practice without such distractions.