Made to hold the Garmin Foretrex 401 GPS and the Garmin Foretrex 101 GPS. Designed with a flap to protect from damage and guard against a light A.D. from your GPS. Elastic arm band for comfort but also allows you to mount the GPS on your SOPMOD butt stock for your M4. Built with a better retention system than any other holder on the market. Made with high quality Mil-spec materials.