Review on PetSpy P620B: Waterproof Dual Dog Training Shock Collar with Vibration, Electric Shock, Beep - Remote Trainer for 2 Dogs, 10-140 lbs by Randy Robinson

Collars last for days on one charge. I usually charge them every night just to be on the safe side. The controller can go more than a week. And the charging time is fast (a few hours at most). I own an acre of land and have had no problems with the distance. I did notice an occasional lag between pressing the button and the collar responding, so I'm deducting a star. I have tried collars that run on batteries and although the batteries last longer than the charge on these collars, changing the batteries was expensive and a hassle. Nice that you can easily charge them. I have two disturbing dogs. One does not respect the fence around our 1 acre yard as his boundary, the other is deaf so it can be difficult to remember. The vibration features work great for getting my hearing impaired pup's attention and the shock/beep feature works well for getting my other dog to respect boundaries. (I have a driveway on both sides of my yard so keeping my dogs within the fence is very important for their safety.)