See I have a CB 3000, CB6000, CB-6000s, and a birdlocked. I was able to pull out of all of them, or more commonly fell out when sleeping or really hot when exercising. Using the Vice now and while a little trickier to put on the first time, has been very comfortable. When using the smallest anti-pullout I have been fully locked in and have not fallen out even when out running. With some lube I probably could pull out but no way I could ever get back in. They are making an even smaller anti-pullout that will be really locked down. Easily the best device without spending the money for a custom fit Mature Metal.