I was very impressed with the Micro after purchasing Doug’s kit and playing around with it. I picked up the two whistle set of Micro’s from AMK and wear one on a breakaway lanyard all the time. It’s just a nice piece of gear and with it’s size really no excuse not to have it with you all the time. Bigger and maybe louder isn’t going to do a person any good unless they have it on them! I'll stick with the Micro as I always have it with me and being a female a whistle is something that could be used to attract attention if attacked too.