I bought this collar for my little guy, a 7 pound terrier mix named Ditka, since it is a much smaller unit than the battery powered ones and I thought it would be easier for him to handle. It proved to be effective keeping him in bounds. But it seems to need charging every 4 days to maintain enough oomph to corral my little critter. After the 4th day of use he seems not to pay any attention to it. At $150 per collar I would think the battery quality would be such that a weekly charge would be enough. I'm kind of disappointed, hence 3 stars.