I ordered the backpack link along with the power+ head, edger & 15" string trimmer because I was unable to find them in any local stores. I really hoped the Backpack link would work as indicated, but it won't power either tool. I tried a 5.0 & 7.5 battery in the backpack, but nothing worked. I ended up using both tools with just the battery and not the Backpack link, which I had been looking forward to. The edger and trimmer both worked great, but my arms were sure tired by the time I finished my 1+ acre lot. I had to take several breaks and found myself resting the trimmer on my hip, which put the head too close to the bend of my arm where I could feel the heat! Unfortunately, I will be returning the Backpack link as soon as I get a chance. I don't know if I have a faulty unit, as I have read some good reviews on this. It is almost as if the battery doesn't lock into place with the contacts even though I could hear the click.