Instruct: Classify Amazon reviews into positive or negative sentiment
Query: It kind of works...sometimes

We have had this system for quite a while and it started off great, over time the transmitter died and we had to get a replacement, now they collars don't work! We have 2 dogs and one of the collars is extremely sensitive and won't the let dog move far from the transmitter and the other can go where ever he wants! The batteries are new btw. I just went to call the dogs inside and had to search for one of them until I finally found him wayyyyy outside his range! We will be using this system for quick trips with the dogs to my parents house, but will still need to watch them. We are upgrading to the dogwatch underground system.