Bought this collar for my 1 yr old 65 lb Blue Heeler from a local pet store . Put it on him at noon yesterday 4/29/2018 .. by 9 am today 4/30/2018  he was sluggish and lathargic . Not playing ball or with his other fur brothers . Not himself at all .. only thing that had changed and new is this damn collar . Took it off him immediatly and 8 hours later he is back to his normal self