You can turn both ends 360 degrees (always hany if you want to see if your fly is open) and you can also extend it to full length (15"). That means you can get into tight spots and weird corners to check line of sight. I have never really needed one but hey, it might come in handy one day. If you want/need one to, they sell them on amazon for 9 pounds. just google "looky periscope"