Dog training collar 600 yards with waterproof Rechargeable

We have a german shepherd, he is very headstrong....this collar worked great to get him to stop terrorizing the two neighbors for fun! He gets a beep first then only one time did we have to low shock him before the beep worked just fine. He wears it whenever we are outside. Now we are working on the grumbling he does because his previous bark collar he figured out that he could grumble and not get shocked!