When I worked up there, the shop had Army surplus ones for us. The few times I wore them, they did OK. I preferred the highest Deet level I could get in a repellent. Thermacell most likely will not be totally effective, but in conjunction with one or both of the others, you should do OK. That is until you go to bed (if you are camping). The constant sound of buzzing makes it hard to get to sleep, especially with the amount of sunlight in the summer.
