This is the collar we use and recommend here at Ozark Wings.  We switched to Dogtra about 4 years ago from another well known collar system and have been really pleased with the reliability of the collars and beepers. The previous collars we used, the beepers rarely lasted a year.  We have some of the Dogtra units are 4 years and counting with minimal upkeep. Purchase of these collars from us also entitles you to call with question and issues you may be having and answered by a training professional