All I have ever used have worked as advertised. I usually use the Toastie Toes on top of my toes on my undersock, instead of underneath. I have found they burn better. I then put a Smart Wool sock over that. With the Hand warmers I only use the 18 hour ones, and have found when I open them in the morning they are good for the entire day. I also think IMOthey burn better than the smaller ones. They are a great addition for cold weather Bowhunting

Dan