Please correct my sentences. The GPS device that I bought last week is the most advanced device in the world in terms of the accuracy and lots of functions in same kind of model that we can carry around GPS. We can also use a smart phone for GPS. But it is useless in mountain because of an inaccuracy. The smart phone’s GPS is said that it have 50~100 meters of error of GPS. Therefore I can’t find my route when I got lost. Sometimes It’s dangerous because I would go wrong way. Especially when I’m in white-out, I can’t believe it. If I was on a cornice, I would fall and to death. In the snowed mountain, I need a high level’s accuracy. And a smart phone is very week agains low temperature, water and shocks. My new one have 3~5 meters of error of GPS. Provide that I make a map that I indicated the way where I walk in advance, I can find the way even if I’m in white-out. Therefore I invest one thousand dollars in it. Is it expensive?