Garmin Alpha 100. Buy once Cry once. My female Brittany's are just under 30 pounds so I use the TT15 mini collar on them and the TT15 standard size collar on the 40 pound male Brittany. The package comes with one collar of your choice, so you will have to buy more collars for other dogs. This system will track up to 4 miles away. I have some friends who bear hunt and they have tested them at range. they swear by them.