I had tried everything for years to stop the barking at every noise or streak of light on a window, failed until the day I received the collar and put it on him.The only issue I experience is one I should have anticipated. As I sat with a guest in family room, he started to go into his very loud and consistent barking.The difference was the first loud bark was NOT followed by more barking. One bark and it stopped. It startled him tho, and he peed each time. If you have a Barker that is a bit insecure and has this tendency, i strongly suggest that you begin the intro outside.Today, the second day, we have had no barking!!!I tried a different shock collar years ago and it did not work, THESE COLLAR WORKED IN 2 DAYS.If i have any further comments, will get back to say. Strongly suggest these collars to help with barking dogs.