Draw back of a Thermacell is that it does not perform well in even the slightest breeze. I guess the repellent is sent downwind or scattered too "thin" to be effective. Works great if it is still. I don't use mine any longer. Not worth the weight to me. Just one more too big a thing to carry. I carry a small bottle of 50% Deet. Does the trick keeping bugs with teeth off of me .... but no doubt deer can scent it. Don't matter to me because I have found nothing that really works all that well to keep deer downwind from scenting me .... except being high and as clean with scent free soaps as practical.