Being from texas and flat ground I worry about being able to breath once I get to 10000 ft I have been getting ready for months im at the point now where i am hiking 5 miles a night with a 50 lb sack of feed in my bad lands 2200 but I know its still going to be tuff hunting in the high elevation and steep drainages. Today someone asked me if I have heard of portable oxygen bars so done some research and found that they have 1.6 ounces bottles of I believe 90 percent pure oxygen. 7" tall and small in diameter and has 12 servings of it.. Has any one out there heard of it or even maybe tried it. If its worth it I will use just about anything to get me in and out (hopefully with a elk on my back) to make my hunt successful