hey guys got to put my two cents in. i'm a tried and true tri-tronics guy, i have the sports series three dog unit works great. i've owned several models and the best so far has been tri-tronics. don't want to get into arguments over which is the best, this has just been the best for me. all of the units out there are good units, just try and pick what will work best for you in the price range you want to spend.