This review is approx two months after use. I have two small dogs under 10 pounds. Live near walking trail with lots of dogs walking by. My dogs barked excessively. Live in the city so can not have that amount of barking. Tried all kinds of positive training to stop the barking. This was my last try. I do NOT use shock. I am not kidding when I say it worked immediately and was so effective after the first bark or two! My concern was if it would effect my dogs in any negative way. It does not!! In fact they sit readily and happily when I put collar on. I have it on lower settings for both sensitivity and vibrate. The life of battery is incredible. I charge once a week but could definitely go longer. Occasionally it will go off when they shake their heads or when they wrestle but it’s not a deal breaker and they don’t seem scared or bothered. Two months later and I let them out without collars from time to time and their barking has dramatically decreased!! I still train with positive reinforcement simultaneously when I have the time because I would like to not have to use these. It’s going well. These are very humane if you use responsibly and on the lowest level that is effective. I rarely write reviews but for me these are a 100% game changer, my dogs are happy dogs and I want others to know. I encourage you to try these. User friendly and the price point is fantastic! Worth the try as it’s not much to lose. Good luck!