All I will add to this is be careful. I have been using GPS since they came out and a unit cost $5K. I have used several different mapping programs including Delorme and PMI and they all have their weak points, (the latest version shows my home about 500 feet from its actual location.) As a general rule they are fantastic but please read the manuals and learn as much as you can about their use before trusting your hunt or your life to them.

Coastie
"Children are tastier than Dogs or Goats and they're far easier for a Leopard to catch" Indian Magistrate Hari Prasad Tivari