I have 2 of them. They work great. Put it on and forget it, no more to loose or to tight. But always remember this collar is for training, as someone I know found out it is not for tying the dog out. I didn't last 2 minutes, and before you even ask it was not me.
I would do anything except put it on and forget it, the rubber bands are prone to break and your collar could be lost. I got one in the mail apparently from BB as it was promised to me as a consolation to some service issues I had. It is now in the trash where it belongs as it lasted one pull from a 6 month old 45 lb pup before the rubber band broke. I don't see a practical use, if you put a regular collar on properly it should not lose contact anyhow.
I have used it and like it but I think it needs to be revised with a stronger wire or something so that if/when the rubber bands break it doesn't fall off and get lost. Especially when training on the water!!
I took the little then plastic wire that comes with it out and replaced with with a peice of line off of a steel leader from a salt water fishing rig.