Masterplus pro spray dog training collar masterplus training collarspecial offer get a universal gas refill free with every masterplus orderedunderstanding your dogyour dog has his own rules for living which are often not compatible with us and our family life eg it might not be acceptable that he steals food digs up the flowerbeds bites you while he is playing etc such bad behaviour can soon become a source of conflict imagine your flowerbeds completely destroyed your favourite armchair ruined