The King size Mattress Jack with the handheld device worked very well on our heavy Kings Down mattress. I was impressed at how high the jack was able to raise our mattress. It definitely helped me get the fitted mattress pad and sheets on. Kind of fun to watch it work too! I was able to place the pump under the foot of the bed, so it is hidden and when I need to use it, I just plug it in and go to work.