The Garmin Alpha is top the line paired with a TT15 collar you can track and train the TT15 also has a vibrate function. They are pretty accurate however heavy overhead cover can cause loss of GPS signal, although Ive only had that happen 1 or 2 times while tracking. Also the range on these collars are tested in wide open areas out west where there are little to no trees per a Garmin rep. However they are pretty close when it comes to actual location. Like someone said the refresh rates can be adjusted, and keep in mind they are like any other GPS system as updates occur you must update your collar and handheld with Garmin.
