Designed for the Garmin Foretrex 401 (may fit other models). We believe that Garmin's Foretrex Series are the best GPS for military use. They provide all important information in a compact and robust package. The Garmin 401 has replaceable batteries, something we consider important for assignments over time. MCD has created a GPS and Map bracelet that combines this good GPS with maps on one arm. This provides good ergonomics and faster orientation. There are also pockets for to-do lists. The armband is attached to the arm with elastic and mesh band.