Do NOT waste your money. The company responded only up until the point when I repeatedly asked HOW to process the 30-day money-back guarantee that is listed on their products, then no response was received again without the intervention of PayPal's claim process. The main problem is not ONLY do the collars not stay on but they DO NOT WORK! 0% of fleas have been killed, deflected, or minimized on ANY of my 6 cats after almost a full month of repeatedly putting their useless collars back on. They claim it is break-away technology and designed that way. However, I have used traditional-style chemical collars before that use actual break-away technology and they only "break-away" when it is entirely necessary for a life-threatening emergency. These collars come off just by the animal scratching, shaking its head, etc. that isn't technology that is POOR craftmanship. I am hoping another company's version of these collars actually works as I do not want to put any chemicals on my animals but this company has made me VERY hesitant to try any other brand.