I researched all the collars on the market before choosing this one. I live in a rural area where the blocks of land are about 2 miles by 2 miles. There are no roads only tracks into the blocks of pine plantations, hardwood forest and cutover land interspersed with farm fields. I wanted to keep my dogs at home during hunting season especially. We raise Redbone coonhounds so they are a natural hunter that are hard to keep up with.I bought three collars and it paid off the first day. Caught the dogs when they came out on the road after a 1.5 mile chase. I could see on the unit where they were, how fast they were closing the distance and was waiting in the road when the deer came out with them right behind. If I had not caught them the next time would have been 2 miles away when they crossed another road.I can't verify what range they work in but at 2 miles in heavy brush they worked fine. The Garmin product does not depend on phone reception , which is pretty bad around here but uses the GPS system. The unit does so much more it will be awhile till I figure it all out but it does what I needed it to do. That is tell me where the dogs are at anytime. Setting up a radius or border lets you know when a dog is leaving so you can stop them before they get to far away.The unit and collars are not cheap but well made and well worth the money.