While I was serving in the Army, I always liked to carry a button compass as a secondary to my primary. I owned several button compasses, including, sunto, silvia ect... All of them failed in the line of duty. While I was in my second tour in Iraq, a british soldier gave me one of his issued ones. I believe they call it a SAS compass. I saw them offered on TAD I think recently. It is the most tank tuff one I have ever used and was consistently within 3 degrees of my primary. The only problem is loosing the dang thing it being so small. I used to keep it in my earplug case with tinder and water purification tablets. Hope I could be some help. If you want, I'll see if I can post a pic.