I used the Fox 40 Micro from the PSP today.

I was taking an advanced compass class from a Phoenix Park Ranger. We were walking a compass course. One of the students missed the marker and walked to the other side of a hill and wondering away. I went up the hill and saw him on the other side and blew my whistle a few times. He looked around and saw me. I then waved him back to the location of the marker.

I keep my Fox 40 Micro in my pocket 24/7. I also have my boys keep one in their pockets 24/7.