1. The collar is too heavy, thus uncomfortable for smaller dogs. 2. Very hard to get the battery in. Needed a pliers to twist the coin so the lid could come off. 3. Hardly beeps but it certainly STINGS! (CRUEL!!!) 4. You have to adjust the battery a few times for the device to work. 5. My poor dog. Despite the heavy collar with piercing and stinging prongs, she continued barking in retaliation to the torture I inflicted upon her. I HATE THIS PRODUCT and I really don't understand the great ratings it received!