So far it is working, I have an English Bulldog four months old that has a bitting issue. No it is not your normal puppy bitting it made me go for stiches twice. One time on the leg and two weeks later on my lips, she jumped on my face while I was correcting her as the trainer taught us.I spent $1.6 k on training at home and at a dog-school and she still has issues. I had to have her on her choke leash inside the apartment all the time and she has not.giben up the strong bitting.The kennel owner did advise she as the litter alpha, but he said that she had the best bulldog temperament as well. And she does, she is sweet but also thinks she can dominate us.So I got this collar sent over to Brazil where we live, it arrived rather quickly within a week. Taxes and duties where paid by the DHL carrier even though it was not necessary, we only pay duties on imports that are over 50 dollars here. I never understand why that happens with shippings to Brazil, they always pay duties even when it is not necessary.The ecollar box inside did not had a seal, but it appeared to be new with the exception of the controller that has tiny scratches on the LCD.At a total cost of 100 dollars I could not send it back, maybe that is why the seller sent it to me, he knew International shipping was not going to complain and lose $100.Things I miss:-A clip on for the controller-The ability to adjust the intensity of the static as you press the static button. My puppy has not felt anything until 20 so I had to keep doing the static until she felt, I was a little scared of that because for me level 4 was enough ( on my skin).-a more comfortable collar, bulldogs have sensitive skin and the material a very harsh nylon.-easier way to adjust for sizeNow for the works:On the first day, I just used the vibration for correction, and bell for positive reinforcement (as a clicker). It worked very well on that first day and we use it for 5 minutes only as it was late.The second day we went for a walk, she stops at every single person to say hello, and I always had to choke her to continue the walk. With the vibration it worked but not all times.She started paying more attention to me without having to give short pokes on the chocking leash as the trainer told us to.At home when playing with my son she started to rough play biting him, then I turned to the static and I had to do the tries until found a correct level. We always use the shiii or ah command with the static so she knows that we are correcting her. She stops and started answering better to the "shiiii" and "ahhh" command when we want her to stop. We have been using it for three days now, so we still have a long way to go.I told my son that she needs to be wearing it everytime she is with us to avoid any other bad accidents, and if not she needs to be on the leash. He does not like the static, but he knows she can hurt us and will get worse as she grows, so she needs to learn to behave within the next two months.Training a dog is hard but I hope this device will make it easier for us. I had several dogs throughout my life , I trained them all without this device.I trained bulldog Campeiro to work with cattle when I was a teenager and lived in a farm, I trained a doberman for agility, I trained a cocker spaniel when I moved to an apartment in the big city. I trained a Whippet as a companion. Never had a biting issue, I was very close to returning the puppy to kennel and cutting out my losses, but we do like the puppy. And the professional trainer is also a behavioral trainer so we felt the need to give it the last shot.In two months I will update here.