Anyone have any experience with these? I've been told by a few people that they're great for keeping mosquitoes away and that they've been using them in their deer stands. I picked one up ($20 at Walgreens) but I haven't opened it yet. It uses butane to activate some sort of pad that has a deterrent in it. I initially thought it would give a deer-alerting smell or sound but everyone has said they don't. Anyone have any input?