They have 32 more satalites so they track
further. If the control says you have
interference With another collar do you
want to change tracking frequnses. Push
no because you Want be able to track
any more on that collar And the other
guy want be able to track his collar either.
I love the t 15 collars I can tell a lot of information also have vibration which is better than a tone. What a lot of people don't know u can buy a camera that mounts on collar. Heart rate body temp and a lot of information battery life is pretty good.