Works absolutely great on my Pitbull who is almost 100 pounds.Vibration strength is great and my boy responds well to it. Even though the shock setting goes up to 100 he’s only at a setting of 5 which is impressive. The remote had a lock feature on it so no mistaken signals. Beep is loud but not annoying. Loud enough for the pet. And I like the fact that it comes with two collars so you can make sure the extra one is charged while using the current one. Battery life has me impressed so far. And it’s super simple to function.